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← 3-2 · Remainder must be less than the divisor · Divisibility and Remainder Reasoning

Remainder must be less than the divisor · 12 practice problems

3.OA.B.63.OA.C.7

Generated variants — 12

Freshly produced from the archetype’s parameters — problem, figure, and solution derived together.

Variant 1 answer: 79

Find the greatest number that \blacksquare can be.

÷8=9\blacksquare \div 8 = 9 \cdots \blacktriangle

Show solution

Understand

A number (the blank) divided by 8 gives quotient 9 and some remainder (the triangle). We want the greatest possible value of the blank, so we make the remainder as large as it can be.

Givens
  • The blank divided by 8 has quotient 9 and remainder equal to the triangle.
  • The remainder is whatever makes the blank largest.
Unknowns
  • The greatest possible value of the blank (the dividend).
Constraints
  • The remainder must be less than the divisor 8.
  • The quotient stays exactly 9.

Plan

#11 Work Backwards · also uses: #6 Guess and Check

Use dividend = divisor times quotient plus remainder. To make the dividend largest while keeping quotient 9, choose the biggest allowed remainder, which is 7.

Execute

#6 Guess and Check 3.OA.B.6
A remainder must be smaller than the divisor 8, so the greatest it can be is 7. A remainder of 8 or more would increase the quotient.
<8=7\blacktriangle < 8 \Rightarrow \blacktriangle = 7
The remainder is always less than the divisor, so 7 is the biggest value that keeps the quotient at 9.
#11 Work Backwards 3.OA.C.7
The dividend equals 8 times the quotient 9, plus the remainder 7.
8×9+7=72+7=798 \times 9 + 7 = 72 + 7 = 79
Multiplying the divisor by the quotient and adding the largest remainder gives the largest number that still divides to give 9.
Answer: 79

Review

Check: 79 divided by 8 is 9 remainder 7, since 8 times 9 is 72 and 79 minus 72 is 7, and 7 is less than 8. Trying 80 would give quotient 10, too big, so 79 is the greatest.

List the candidates (tool 2): dividends giving quotient 9 are 72 (r 0) up to 79 (r 7); the next, 80, bumps the quotient to 10, so 79 is the maximum.

Standards · min grade 3

  • 3.OA.B.6 Understand division as an unknown-factor problem — Recognizing the remainder must be less than 8, so its largest value is 7.
  • 3.OA.C.7 Fluently multiply and divide within 100 — Computing 8 times 9 plus 7 to get the greatest dividend.
💡 This only needs Grade 3 division: the remainder maxes out at one less than the divisor, then multiply back!
Variant 2 answer: 71

Find the greatest number that \blacksquare can be.

÷9=7\blacksquare \div 9 = 7 \cdots \blacktriangle

Show solution

Understand

A number (the blank) divided by 9 gives quotient 7 and some remainder (the triangle). We want the greatest possible value of the blank, so we make the remainder as large as it can be.

Givens
  • The blank divided by 9 has quotient 7 and remainder equal to the triangle.
  • The remainder is whatever makes the blank largest.
Unknowns
  • The greatest possible value of the blank (the dividend).
Constraints
  • The remainder must be less than the divisor 9.
  • The quotient stays exactly 7.

Plan

#11 Work Backwards · also uses: #6 Guess and Check

Use dividend = divisor times quotient plus remainder. To make the dividend largest while keeping quotient 7, choose the biggest allowed remainder, which is 8.

Execute

#6 Guess and Check 3.OA.B.6
A remainder must be smaller than the divisor 9, so the greatest it can be is 8. A remainder of 9 or more would increase the quotient.
<9=8\blacktriangle < 9 \Rightarrow \blacktriangle = 8
The remainder is always less than the divisor, so 8 is the biggest value that keeps the quotient at 7.
#11 Work Backwards 3.OA.C.7
The dividend equals 9 times the quotient 7, plus the remainder 8.
9×7+8=63+8=719 \times 7 + 8 = 63 + 8 = 71
Multiplying the divisor by the quotient and adding the largest remainder gives the largest number that still divides to give 7.
Answer: 71

Review

Check: 71 divided by 9 is 7 remainder 8, since 9 times 7 is 63 and 71 minus 63 is 8, and 8 is less than 9. Trying 72 would give quotient 8, too big, so 71 is the greatest.

List the candidates (tool 2): dividends giving quotient 7 are 63 (r 0) up to 71 (r 8); the next, 72, bumps the quotient to 8, so 71 is the maximum.

Standards · min grade 3

  • 3.OA.B.6 Understand division as an unknown-factor problem — Recognizing the remainder must be less than 9, so its largest value is 8.
  • 3.OA.C.7 Fluently multiply and divide within 100 — Computing 9 times 7 plus 8 to get the greatest dividend.
💡 This only needs Grade 3 division: the remainder maxes out at one less than the divisor, then multiply back!
Variant 3 answer: 89

Find the greatest number that \blacksquare can be.

÷9=9\blacksquare \div 9 = 9 \cdots \blacktriangle

Show solution

Understand

A number (the blank) divided by 9 gives quotient 9 and some remainder (the triangle). We want the greatest possible value of the blank, so we make the remainder as large as it can be.

Givens
  • The blank divided by 9 has quotient 9 and remainder equal to the triangle.
  • The remainder is whatever makes the blank largest.
Unknowns
  • The greatest possible value of the blank (the dividend).
Constraints
  • The remainder must be less than the divisor 9.
  • The quotient stays exactly 9.

Plan

#11 Work Backwards · also uses: #6 Guess and Check

Use dividend = divisor times quotient plus remainder. To make the dividend largest while keeping quotient 9, choose the biggest allowed remainder, which is 8.

Execute

#6 Guess and Check 3.OA.B.6
A remainder must be smaller than the divisor 9, so the greatest it can be is 8. A remainder of 9 or more would increase the quotient.
<9=8\blacktriangle < 9 \Rightarrow \blacktriangle = 8
The remainder is always less than the divisor, so 8 is the biggest value that keeps the quotient at 9.
#11 Work Backwards 3.OA.C.7
The dividend equals 9 times the quotient 9, plus the remainder 8.
9×9+8=81+8=899 \times 9 + 8 = 81 + 8 = 89
Multiplying the divisor by the quotient and adding the largest remainder gives the largest number that still divides to give 9.
Answer: 89

Review

Check: 89 divided by 9 is 9 remainder 8, since 9 times 9 is 81 and 89 minus 81 is 8, and 8 is less than 9. Trying 90 would give quotient 10, too big, so 89 is the greatest.

List the candidates (tool 2): dividends giving quotient 9 are 81 (r 0) up to 89 (r 8); the next, 90, bumps the quotient to 10, so 89 is the maximum.

Standards · min grade 3

  • 3.OA.B.6 Understand division as an unknown-factor problem — Recognizing the remainder must be less than 9, so its largest value is 8.
  • 3.OA.C.7 Fluently multiply and divide within 100 — Computing 9 times 9 plus 8 to get the greatest dividend.
💡 This only needs Grade 3 division: the remainder maxes out at one less than the divisor, then multiply back!
Variant 4 answer: 64

Find the greatest number that \blacksquare can be.

÷5=12\blacksquare \div 5 = 12 \cdots \blacktriangle

Show solution

Understand

A number (the blank) divided by 5 gives quotient 12 and some remainder (the triangle). We want the greatest possible value of the blank, so we make the remainder as large as it can be.

Givens
  • The blank divided by 5 has quotient 12 and remainder equal to the triangle.
  • The remainder is whatever makes the blank largest.
Unknowns
  • The greatest possible value of the blank (the dividend).
Constraints
  • The remainder must be less than the divisor 5.
  • The quotient stays exactly 12.

Plan

#11 Work Backwards · also uses: #6 Guess and Check

Use dividend = divisor times quotient plus remainder. To make the dividend largest while keeping quotient 12, choose the biggest allowed remainder, which is 4.

Execute

#6 Guess and Check 3.OA.B.6
A remainder must be smaller than the divisor 5, so the greatest it can be is 4. A remainder of 5 or more would increase the quotient.
<5=4\blacktriangle < 5 \Rightarrow \blacktriangle = 4
The remainder is always less than the divisor, so 4 is the biggest value that keeps the quotient at 12.
#11 Work Backwards 3.OA.C.7
The dividend equals 5 times the quotient 12, plus the remainder 4.
5×12+4=60+4=645 \times 12 + 4 = 60 + 4 = 64
Multiplying the divisor by the quotient and adding the largest remainder gives the largest number that still divides to give 12.
Answer: 64

Review

Check: 64 divided by 5 is 12 remainder 4, since 5 times 12 is 60 and 64 minus 60 is 4, and 4 is less than 5. Trying 65 would give quotient 13, too big, so 64 is the greatest.

List the candidates (tool 2): dividends giving quotient 12 are 60 (r 0) up to 64 (r 4); the next, 65, bumps the quotient to 13, so 64 is the maximum.

Standards · min grade 3

  • 3.OA.B.6 Understand division as an unknown-factor problem — Recognizing the remainder must be less than 5, so its largest value is 4.
  • 3.OA.C.7 Fluently multiply and divide within 100 — Computing 5 times 12 plus 4 to get the greatest dividend.
💡 This only needs Grade 3 division: the remainder maxes out at one less than the divisor, then multiply back!
Variant 5 answer: 83

Find the greatest number that \blacksquare can be.

÷7=11\blacksquare \div 7 = 11 \cdots \blacktriangle

Show solution

Understand

A number (the blank) divided by 7 gives quotient 11 and some remainder (the triangle). We want the greatest possible value of the blank, so we make the remainder as large as it can be.

Givens
  • The blank divided by 7 has quotient 11 and remainder equal to the triangle.
  • The remainder is whatever makes the blank largest.
Unknowns
  • The greatest possible value of the blank (the dividend).
Constraints
  • The remainder must be less than the divisor 7.
  • The quotient stays exactly 11.

Plan

#11 Work Backwards · also uses: #6 Guess and Check

Use dividend = divisor times quotient plus remainder. To make the dividend largest while keeping quotient 11, choose the biggest allowed remainder, which is 6.

Execute

#6 Guess and Check 3.OA.B.6
A remainder must be smaller than the divisor 7, so the greatest it can be is 6. A remainder of 7 or more would increase the quotient.
<7=6\blacktriangle < 7 \Rightarrow \blacktriangle = 6
The remainder is always less than the divisor, so 6 is the biggest value that keeps the quotient at 11.
#11 Work Backwards 3.OA.C.7
The dividend equals 7 times the quotient 11, plus the remainder 6.
7×11+6=77+6=837 \times 11 + 6 = 77 + 6 = 83
Multiplying the divisor by the quotient and adding the largest remainder gives the largest number that still divides to give 11.
Answer: 83

Review

Check: 83 divided by 7 is 11 remainder 6, since 7 times 11 is 77 and 83 minus 77 is 6, and 6 is less than 7. Trying 84 would give quotient 12, too big, so 83 is the greatest.

List the candidates (tool 2): dividends giving quotient 11 are 77 (r 0) up to 83 (r 6); the next, 84, bumps the quotient to 12, so 83 is the maximum.

Standards · min grade 3

  • 3.OA.B.6 Understand division as an unknown-factor problem — Recognizing the remainder must be less than 7, so its largest value is 6.
  • 3.OA.C.7 Fluently multiply and divide within 100 — Computing 7 times 11 plus 6 to get the greatest dividend.
💡 This only needs Grade 3 division: the remainder maxes out at one less than the divisor, then multiply back!
Variant 6 answer: 55

Find the greatest number that \blacksquare can be.

÷8=6\blacksquare \div 8 = 6 \cdots \blacktriangle

Show solution

Understand

A number (the blank) divided by 8 gives quotient 6 and some remainder (the triangle). We want the greatest possible value of the blank, so we make the remainder as large as it can be.

Givens
  • The blank divided by 8 has quotient 6 and remainder equal to the triangle.
  • The remainder is whatever makes the blank largest.
Unknowns
  • The greatest possible value of the blank (the dividend).
Constraints
  • The remainder must be less than the divisor 8.
  • The quotient stays exactly 6.

Plan

#11 Work Backwards · also uses: #6 Guess and Check

Use dividend = divisor times quotient plus remainder. To make the dividend largest while keeping quotient 6, choose the biggest allowed remainder, which is 7.

Execute

#6 Guess and Check 3.OA.B.6
A remainder must be smaller than the divisor 8, so the greatest it can be is 7. A remainder of 8 or more would increase the quotient.
<8=7\blacktriangle < 8 \Rightarrow \blacktriangle = 7
The remainder is always less than the divisor, so 7 is the biggest value that keeps the quotient at 6.
#11 Work Backwards 3.OA.C.7
The dividend equals 8 times the quotient 6, plus the remainder 7.
8×6+7=48+7=558 \times 6 + 7 = 48 + 7 = 55
Multiplying the divisor by the quotient and adding the largest remainder gives the largest number that still divides to give 6.
Answer: 55

Review

Check: 55 divided by 8 is 6 remainder 7, since 8 times 6 is 48 and 55 minus 48 is 7, and 7 is less than 8. Trying 56 would give quotient 7, too big, so 55 is the greatest.

List the candidates (tool 2): dividends giving quotient 6 are 48 (r 0) up to 55 (r 7); the next, 56, bumps the quotient to 7, so 55 is the maximum.

Standards · min grade 3

  • 3.OA.B.6 Understand division as an unknown-factor problem — Recognizing the remainder must be less than 8, so its largest value is 7.
  • 3.OA.C.7 Fluently multiply and divide within 100 — Computing 8 times 6 plus 7 to get the greatest dividend.
💡 This only needs Grade 3 division: the remainder maxes out at one less than the divisor, then multiply back!
Variant 7 answer: 65

Find the greatest number that \blacksquare can be.

÷6=10\blacksquare \div 6 = 10 \cdots \blacktriangle

Show solution

Understand

A number (the blank) divided by 6 gives quotient 10 and some remainder (the triangle). We want the greatest possible value of the blank, so we make the remainder as large as it can be.

Givens
  • The blank divided by 6 has quotient 10 and remainder equal to the triangle.
  • The remainder is whatever makes the blank largest.
Unknowns
  • The greatest possible value of the blank (the dividend).
Constraints
  • The remainder must be less than the divisor 6.
  • The quotient stays exactly 10.

Plan

#11 Work Backwards · also uses: #6 Guess and Check

Use dividend = divisor times quotient plus remainder. To make the dividend largest while keeping quotient 10, choose the biggest allowed remainder, which is 5.

Execute

#6 Guess and Check 3.OA.B.6
A remainder must be smaller than the divisor 6, so the greatest it can be is 5. A remainder of 6 or more would increase the quotient.
<6=5\blacktriangle < 6 \Rightarrow \blacktriangle = 5
The remainder is always less than the divisor, so 5 is the biggest value that keeps the quotient at 10.
#11 Work Backwards 3.OA.C.7
The dividend equals 6 times the quotient 10, plus the remainder 5.
6×10+5=60+5=656 \times 10 + 5 = 60 + 5 = 65
Multiplying the divisor by the quotient and adding the largest remainder gives the largest number that still divides to give 10.
Answer: 65

Review

Check: 65 divided by 6 is 10 remainder 5, since 6 times 10 is 60 and 65 minus 60 is 5, and 5 is less than 6. Trying 66 would give quotient 11, too big, so 65 is the greatest.

List the candidates (tool 2): dividends giving quotient 10 are 60 (r 0) up to 65 (r 5); the next, 66, bumps the quotient to 11, so 65 is the maximum.

Standards · min grade 3

  • 3.OA.B.6 Understand division as an unknown-factor problem — Recognizing the remainder must be less than 6, so its largest value is 5.
  • 3.OA.C.7 Fluently multiply and divide within 100 — Computing 6 times 10 plus 5 to get the greatest dividend.
💡 This only needs Grade 3 division: the remainder maxes out at one less than the divisor, then multiply back!
Variant 8 answer: 95

Find the greatest number that \blacksquare can be.

÷8=11\blacksquare \div 8 = 11 \cdots \blacktriangle

Show solution

Understand

A number (the blank) divided by 8 gives quotient 11 and some remainder (the triangle). We want the greatest possible value of the blank, so we make the remainder as large as it can be.

Givens
  • The blank divided by 8 has quotient 11 and remainder equal to the triangle.
  • The remainder is whatever makes the blank largest.
Unknowns
  • The greatest possible value of the blank (the dividend).
Constraints
  • The remainder must be less than the divisor 8.
  • The quotient stays exactly 11.

Plan

#11 Work Backwards · also uses: #6 Guess and Check

Use dividend = divisor times quotient plus remainder. To make the dividend largest while keeping quotient 11, choose the biggest allowed remainder, which is 7.

Execute

#6 Guess and Check 3.OA.B.6
A remainder must be smaller than the divisor 8, so the greatest it can be is 7. A remainder of 8 or more would increase the quotient.
<8=7\blacktriangle < 8 \Rightarrow \blacktriangle = 7
The remainder is always less than the divisor, so 7 is the biggest value that keeps the quotient at 11.
#11 Work Backwards 3.OA.C.7
The dividend equals 8 times the quotient 11, plus the remainder 7.
8×11+7=88+7=958 \times 11 + 7 = 88 + 7 = 95
Multiplying the divisor by the quotient and adding the largest remainder gives the largest number that still divides to give 11.
Answer: 95

Review

Check: 95 divided by 8 is 11 remainder 7, since 8 times 11 is 88 and 95 minus 88 is 7, and 7 is less than 8. Trying 96 would give quotient 12, too big, so 95 is the greatest.

List the candidates (tool 2): dividends giving quotient 11 are 88 (r 0) up to 95 (r 7); the next, 96, bumps the quotient to 12, so 95 is the maximum.

Standards · min grade 3

  • 3.OA.B.6 Understand division as an unknown-factor problem — Recognizing the remainder must be less than 8, so its largest value is 7.
  • 3.OA.C.7 Fluently multiply and divide within 100 — Computing 8 times 11 plus 7 to get the greatest dividend.
💡 This only needs Grade 3 division: the remainder maxes out at one less than the divisor, then multiply back!
Variant 9 answer: 62

Find the greatest number that \blacksquare can be.

÷7=8\blacksquare \div 7 = 8 \cdots \blacktriangle

Show solution

Understand

A number (the blank) divided by 7 gives quotient 8 and some remainder (the triangle). We want the greatest possible value of the blank, so we make the remainder as large as it can be.

Givens
  • The blank divided by 7 has quotient 8 and remainder equal to the triangle.
  • The remainder is whatever makes the blank largest.
Unknowns
  • The greatest possible value of the blank (the dividend).
Constraints
  • The remainder must be less than the divisor 7.
  • The quotient stays exactly 8.

Plan

#11 Work Backwards · also uses: #6 Guess and Check

Use dividend = divisor times quotient plus remainder. To make the dividend largest while keeping quotient 8, choose the biggest allowed remainder, which is 6.

Execute

#6 Guess and Check 3.OA.B.6
A remainder must be smaller than the divisor 7, so the greatest it can be is 6. A remainder of 7 or more would increase the quotient.
<7=6\blacktriangle < 7 \Rightarrow \blacktriangle = 6
The remainder is always less than the divisor, so 6 is the biggest value that keeps the quotient at 8.
#11 Work Backwards 3.OA.C.7
The dividend equals 7 times the quotient 8, plus the remainder 6.
7×8+6=56+6=627 \times 8 + 6 = 56 + 6 = 62
Multiplying the divisor by the quotient and adding the largest remainder gives the largest number that still divides to give 8.
Answer: 62

Review

Check: 62 divided by 7 is 8 remainder 6, since 7 times 8 is 56 and 62 minus 56 is 6, and 6 is less than 7. Trying 63 would give quotient 9, too big, so 62 is the greatest.

List the candidates (tool 2): dividends giving quotient 8 are 56 (r 0) up to 62 (r 6); the next, 63, bumps the quotient to 9, so 62 is the maximum.

Standards · min grade 3

  • 3.OA.B.6 Understand division as an unknown-factor problem — Recognizing the remainder must be less than 7, so its largest value is 6.
  • 3.OA.C.7 Fluently multiply and divide within 100 — Computing 7 times 8 plus 6 to get the greatest dividend.
💡 This only needs Grade 3 division: the remainder maxes out at one less than the divisor, then multiply back!
Variant 10 answer: 74

Find the greatest number that \blacksquare can be.

÷5=14\blacksquare \div 5 = 14 \cdots \blacktriangle

Show solution

Understand

A number (the blank) divided by 5 gives quotient 14 and some remainder (the triangle). We want the greatest possible value of the blank, so we make the remainder as large as it can be.

Givens
  • The blank divided by 5 has quotient 14 and remainder equal to the triangle.
  • The remainder is whatever makes the blank largest.
Unknowns
  • The greatest possible value of the blank (the dividend).
Constraints
  • The remainder must be less than the divisor 5.
  • The quotient stays exactly 14.

Plan

#11 Work Backwards · also uses: #6 Guess and Check

Use dividend = divisor times quotient plus remainder. To make the dividend largest while keeping quotient 14, choose the biggest allowed remainder, which is 4.

Execute

#6 Guess and Check 3.OA.B.6
A remainder must be smaller than the divisor 5, so the greatest it can be is 4. A remainder of 5 or more would increase the quotient.
<5=4\blacktriangle < 5 \Rightarrow \blacktriangle = 4
The remainder is always less than the divisor, so 4 is the biggest value that keeps the quotient at 14.
#11 Work Backwards 3.OA.C.7
The dividend equals 5 times the quotient 14, plus the remainder 4.
5×14+4=70+4=745 \times 14 + 4 = 70 + 4 = 74
Multiplying the divisor by the quotient and adding the largest remainder gives the largest number that still divides to give 14.
Answer: 74

Review

Check: 74 divided by 5 is 14 remainder 4, since 5 times 14 is 70 and 74 minus 70 is 4, and 4 is less than 5. Trying 75 would give quotient 15, too big, so 74 is the greatest.

List the candidates (tool 2): dividends giving quotient 14 are 70 (r 0) up to 74 (r 4); the next, 75, bumps the quotient to 15, so 74 is the maximum.

Standards · min grade 3

  • 3.OA.B.6 Understand division as an unknown-factor problem — Recognizing the remainder must be less than 5, so its largest value is 4.
  • 3.OA.C.7 Fluently multiply and divide within 100 — Computing 5 times 14 plus 4 to get the greatest dividend.
💡 This only needs Grade 3 division: the remainder maxes out at one less than the divisor, then multiply back!
Variant 11 answer: 63

Find the greatest number that \blacksquare can be.

÷4=15\blacksquare \div 4 = 15 \cdots \blacktriangle

Show solution

Understand

A number (the blank) divided by 4 gives quotient 15 and some remainder (the triangle). We want the greatest possible value of the blank, so we make the remainder as large as it can be.

Givens
  • The blank divided by 4 has quotient 15 and remainder equal to the triangle.
  • The remainder is whatever makes the blank largest.
Unknowns
  • The greatest possible value of the blank (the dividend).
Constraints
  • The remainder must be less than the divisor 4.
  • The quotient stays exactly 15.

Plan

#11 Work Backwards · also uses: #6 Guess and Check

Use dividend = divisor times quotient plus remainder. To make the dividend largest while keeping quotient 15, choose the biggest allowed remainder, which is 3.

Execute

#6 Guess and Check 3.OA.B.6
A remainder must be smaller than the divisor 4, so the greatest it can be is 3. A remainder of 4 or more would increase the quotient.
<4=3\blacktriangle < 4 \Rightarrow \blacktriangle = 3
The remainder is always less than the divisor, so 3 is the biggest value that keeps the quotient at 15.
#11 Work Backwards 3.OA.C.7
The dividend equals 4 times the quotient 15, plus the remainder 3.
4×15+3=60+3=634 \times 15 + 3 = 60 + 3 = 63
Multiplying the divisor by the quotient and adding the largest remainder gives the largest number that still divides to give 15.
Answer: 63

Review

Check: 63 divided by 4 is 15 remainder 3, since 4 times 15 is 60 and 63 minus 60 is 3, and 3 is less than 4. Trying 64 would give quotient 16, too big, so 63 is the greatest.

List the candidates (tool 2): dividends giving quotient 15 are 60 (r 0) up to 63 (r 3); the next, 64, bumps the quotient to 16, so 63 is the maximum.

Standards · min grade 3

  • 3.OA.B.6 Understand division as an unknown-factor problem — Recognizing the remainder must be less than 4, so its largest value is 3.
  • 3.OA.C.7 Fluently multiply and divide within 100 — Computing 4 times 15 plus 3 to get the greatest dividend.
💡 This only needs Grade 3 division: the remainder maxes out at one less than the divisor, then multiply back!
Variant 12 answer: 59

Find the greatest number that \blacksquare can be.

÷6=9\blacksquare \div 6 = 9 \cdots \blacktriangle

Show solution

Understand

A number (the blank) divided by 6 gives quotient 9 and some remainder (the triangle). We want the greatest possible value of the blank, so we make the remainder as large as it can be.

Givens
  • The blank divided by 6 has quotient 9 and remainder equal to the triangle.
  • The remainder is whatever makes the blank largest.
Unknowns
  • The greatest possible value of the blank (the dividend).
Constraints
  • The remainder must be less than the divisor 6.
  • The quotient stays exactly 9.

Plan

#11 Work Backwards · also uses: #6 Guess and Check

Use dividend = divisor times quotient plus remainder. To make the dividend largest while keeping quotient 9, choose the biggest allowed remainder, which is 5.

Execute

#6 Guess and Check 3.OA.B.6
A remainder must be smaller than the divisor 6, so the greatest it can be is 5. A remainder of 6 or more would increase the quotient.
<6=5\blacktriangle < 6 \Rightarrow \blacktriangle = 5
The remainder is always less than the divisor, so 5 is the biggest value that keeps the quotient at 9.
#11 Work Backwards 3.OA.C.7
The dividend equals 6 times the quotient 9, plus the remainder 5.
6×9+5=54+5=596 \times 9 + 5 = 54 + 5 = 59
Multiplying the divisor by the quotient and adding the largest remainder gives the largest number that still divides to give 9.
Answer: 59

Review

Check: 59 divided by 6 is 9 remainder 5, since 6 times 9 is 54 and 59 minus 54 is 5, and 5 is less than 6. Trying 60 would give quotient 10, too big, so 59 is the greatest.

List the candidates (tool 2): dividends giving quotient 9 are 54 (r 0) up to 59 (r 5); the next, 60, bumps the quotient to 10, so 59 is the maximum.

Standards · min grade 3

  • 3.OA.B.6 Understand division as an unknown-factor problem — Recognizing the remainder must be less than 6, so its largest value is 5.
  • 3.OA.C.7 Fluently multiply and divide within 100 — Computing 6 times 9 plus 5 to get the greatest dividend.
💡 This only needs Grade 3 division: the remainder maxes out at one less than the divisor, then multiply back!