← Divisor times quotient plus remainder gives the number back · Divisibility and Remainder Reasoning

Divisor times quotient plus remainder gives the number back · 12 practice problems

6.NS.B.36.NS.B.2

Generated variants — 12

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

Variant 1 easy answer: 5.5

A number was divided by 4.34.3 and the quotient taken only as far as its whole-number part, giving a quotient of 77 and a remainder of 1.81.8. If the same number is divided by 6.66.6 in the same way, what is the remainder?

Show solution
1 · Understandwhat's really being asked

Some number over 4.3 gives 7 remainder 1.8. Divided by 6.6 the same way, we want the new remainder.

Givens
  • Dividing by 4.3 gives quotient 7 and remainder 1.8.
  • The same number is then divided by 6.6.
  • In both cases the quotient is taken only as far as its whole-number part.
Unknowns
  • The remainder from the second division.
Constraints
  • The number itself is never stated.
2 · Planchoose the strategy

#11 Work Backwards · also uses: #7 Identify Subproblems#8 Analyze the Units

Nothing can be done with the second divisor until the number is known. Divisor times quotient plus remainder rebuilds it exactly, and then the second division is just a division.

3 · Execute3 carry out the plan

1Rebuild the number

#11 Work Backwards 6.NS.B.2
Multiply the divisor by the quotient and add the remainder.
4.3×7+1.8=31.94.3 \times 7 + 1.8 = 31.9
The number is 31.9.

2See how many 6.6s fit

#7 Identify Subproblems 6.NS.B.3
4 of them come to 26.4, and one more would overshoot.
6.6×4=26.46.6 \times 4 = 26.4
The whole-number quotient is 4.

3Take that off the number

#8 Analyze the Units 6.NS.B.3
What is left over is the remainder.
31.926.4=5.531.9 - 26.4 = 5.5
The remainder is 5.5.
Answer: 5.5
4 · Reviewdoes it hold up?

The remainder 5.5 is smaller than the divisor 6.6, as every remainder must be -- otherwise another whole 6.6 would have fitted.

Another way: Rebuilding from the second division instead, 6.6×4+5.5=31.96.6 \times 4 + 5.5 = 31.9, gives back the same number, which is the check that both divisions describe it.

Standardsmin grade 6
  • 6.NS.B.3 Fluently add, subtract, multiply, divide multi-digit decimals — Dividing and subtracting decimals.
  • 6.NS.B.2 Fluently divide multi-digit numbers — Using divisor times quotient plus remainder.
💡Takeaway. A quotient and a remainder together say exactly what the number was. You can always build it back.
Variant 2 easy answer: 3.1

A number was divided by 4.84.8 and the quotient taken only as far as its whole-number part, giving a quotient of 66 and a remainder of 2.72.7. If the same number is divided by 7.17.1 in the same way, what is the remainder?

Show solution
1 · Understandwhat's really being asked

Some number over 4.8 gives 6 remainder 2.7. Divided by 7.1 the same way, we want the new remainder.

Givens
  • Dividing by 4.8 gives quotient 6 and remainder 2.7.
  • The same number is then divided by 7.1.
  • In both cases the quotient is taken only as far as its whole-number part.
Unknowns
  • The remainder from the second division.
Constraints
  • The number itself is never stated.
2 · Planchoose the strategy

#11 Work Backwards · also uses: #7 Identify Subproblems#8 Analyze the Units

Nothing can be done with the second divisor until the number is known. Divisor times quotient plus remainder rebuilds it exactly, and then the second division is just a division.

3 · Execute3 carry out the plan

1Rebuild the number

#11 Work Backwards 6.NS.B.2
Multiply the divisor by the quotient and add the remainder.
4.8×6+2.7=31.54.8 \times 6 + 2.7 = 31.5
The number is 31.5.

2See how many 7.1s fit

#7 Identify Subproblems 6.NS.B.3
4 of them come to 28.4, and one more would overshoot.
7.1×4=28.47.1 \times 4 = 28.4
The whole-number quotient is 4.

3Take that off the number

#8 Analyze the Units 6.NS.B.3
What is left over is the remainder.
31.528.4=3.131.5 - 28.4 = 3.1
The remainder is 3.1.
Answer: 3.1
4 · Reviewdoes it hold up?

The remainder 3.1 is smaller than the divisor 7.1, as every remainder must be -- otherwise another whole 7.1 would have fitted.

Another way: Rebuilding from the second division instead, 7.1×4+3.1=31.57.1 \times 4 + 3.1 = 31.5, gives back the same number, which is the check that both divisions describe it.

Standardsmin grade 6
  • 6.NS.B.3 Fluently add, subtract, multiply, divide multi-digit decimals — Dividing and subtracting decimals.
  • 6.NS.B.2 Fluently divide multi-digit numbers — Using divisor times quotient plus remainder.
💡Takeaway. A quotient and a remainder together say exactly what the number was. You can always build it back.
Variant 3 easy answer: 1

A number was divided by 5.25.2 and the quotient taken only as far as its whole-number part, giving a quotient of 44 and a remainder of 2.12.1. If the same number is divided by 7.37.3 in the same way, what is the remainder?

Show solution
1 · Understandwhat's really being asked

Some number over 5.2 gives 4 remainder 2.1. Divided by 7.3 the same way, we want the new remainder.

Givens
  • Dividing by 5.2 gives quotient 4 and remainder 2.1.
  • The same number is then divided by 7.3.
  • In both cases the quotient is taken only as far as its whole-number part.
Unknowns
  • The remainder from the second division.
Constraints
  • The number itself is never stated.
2 · Planchoose the strategy

#11 Work Backwards · also uses: #7 Identify Subproblems#8 Analyze the Units

Nothing can be done with the second divisor until the number is known. Divisor times quotient plus remainder rebuilds it exactly, and then the second division is just a division.

3 · Execute3 carry out the plan

1Rebuild the number

#11 Work Backwards 6.NS.B.2
Multiply the divisor by the quotient and add the remainder.
5.2×4+2.1=22.95.2 \times 4 + 2.1 = 22.9
The number is 22.9.

2See how many 7.3s fit

#7 Identify Subproblems 6.NS.B.3
3 of them come to 21.9, and one more would overshoot.
7.3×3=21.97.3 \times 3 = 21.9
The whole-number quotient is 3.

3Take that off the number

#8 Analyze the Units 6.NS.B.3
What is left over is the remainder.
22.921.9=122.9 - 21.9 = 1
The remainder is 1.
Answer: 1
4 · Reviewdoes it hold up?

The remainder 1 is smaller than the divisor 7.3, as every remainder must be -- otherwise another whole 7.3 would have fitted.

Another way: Rebuilding from the second division instead, 7.3×3+1=22.97.3 \times 3 + 1 = 22.9, gives back the same number, which is the check that both divisions describe it.

Standardsmin grade 6
  • 6.NS.B.3 Fluently add, subtract, multiply, divide multi-digit decimals — Dividing and subtracting decimals.
  • 6.NS.B.2 Fluently divide multi-digit numbers — Using divisor times quotient plus remainder.
💡Takeaway. A quotient and a remainder together say exactly what the number was. You can always build it back.
Variant 4 easy answer: 6.6

A number was divided by 7.47.4 and the quotient taken only as far as its whole-number part, giving a quotient of 77 and a remainder of 4.64.6. If the same number is divided by 8.38.3 in the same way, what is the remainder?

Show solution
1 · Understandwhat's really being asked

Some number over 7.4 gives 7 remainder 4.6. Divided by 8.3 the same way, we want the new remainder.

Givens
  • Dividing by 7.4 gives quotient 7 and remainder 4.6.
  • The same number is then divided by 8.3.
  • In both cases the quotient is taken only as far as its whole-number part.
Unknowns
  • The remainder from the second division.
Constraints
  • The number itself is never stated.
2 · Planchoose the strategy

#11 Work Backwards · also uses: #7 Identify Subproblems#8 Analyze the Units

Nothing can be done with the second divisor until the number is known. Divisor times quotient plus remainder rebuilds it exactly, and then the second division is just a division.

3 · Execute3 carry out the plan

1Rebuild the number

#11 Work Backwards 6.NS.B.2
Multiply the divisor by the quotient and add the remainder.
7.4×7+4.6=56.47.4 \times 7 + 4.6 = 56.4
The number is 56.4.

2See how many 8.3s fit

#7 Identify Subproblems 6.NS.B.3
6 of them come to 49.8, and one more would overshoot.
8.3×6=49.88.3 \times 6 = 49.8
The whole-number quotient is 6.

3Take that off the number

#8 Analyze the Units 6.NS.B.3
What is left over is the remainder.
56.449.8=6.656.4 - 49.8 = 6.6
The remainder is 6.6.
Answer: 6.6
4 · Reviewdoes it hold up?

The remainder 6.6 is smaller than the divisor 8.3, as every remainder must be -- otherwise another whole 8.3 would have fitted.

Another way: Rebuilding from the second division instead, 8.3×6+6.6=56.48.3 \times 6 + 6.6 = 56.4, gives back the same number, which is the check that both divisions describe it.

Standardsmin grade 6
  • 6.NS.B.3 Fluently add, subtract, multiply, divide multi-digit decimals — Dividing and subtracting decimals.
  • 6.NS.B.2 Fluently divide multi-digit numbers — Using divisor times quotient plus remainder.
💡Takeaway. A quotient and a remainder together say exactly what the number was. You can always build it back.
Variant 5 medium answer: 6.9

A number was divided by 3.73.7 and the quotient taken only as far as its whole-number part, giving a quotient of 88 and a remainder of 2.52.5. If the same number is divided by 8.48.4 in the same way, what is the remainder?

Show solution
1 · Understandwhat's really being asked

Some number over 3.7 gives 8 remainder 2.5. Divided by 8.4 the same way, we want the new remainder.

Givens
  • Dividing by 3.7 gives quotient 8 and remainder 2.5.
  • The same number is then divided by 8.4.
  • In both cases the quotient is taken only as far as its whole-number part.
Unknowns
  • The remainder from the second division.
Constraints
  • The number itself is never stated.
2 · Planchoose the strategy

#11 Work Backwards · also uses: #7 Identify Subproblems#8 Analyze the Units

Nothing can be done with the second divisor until the number is known. Divisor times quotient plus remainder rebuilds it exactly, and then the second division is just a division.

3 · Execute3 carry out the plan

1Rebuild the number

#11 Work Backwards 6.NS.B.2
Multiply the divisor by the quotient and add the remainder.
3.7×8+2.5=32.13.7 \times 8 + 2.5 = 32.1
The number is 32.1.

2See how many 8.4s fit

#7 Identify Subproblems 6.NS.B.3
3 of them come to 25.2, and one more would overshoot.
8.4×3=25.28.4 \times 3 = 25.2
The whole-number quotient is 3.

3Take that off the number

#8 Analyze the Units 6.NS.B.3
What is left over is the remainder.
32.125.2=6.932.1 - 25.2 = 6.9
The remainder is 6.9.
Answer: 6.9
4 · Reviewdoes it hold up?

The remainder 6.9 is smaller than the divisor 8.4, as every remainder must be -- otherwise another whole 8.4 would have fitted.

Another way: Rebuilding from the second division instead, 8.4×3+6.9=32.18.4 \times 3 + 6.9 = 32.1, gives back the same number, which is the check that both divisions describe it.

Standardsmin grade 6
  • 6.NS.B.3 Fluently add, subtract, multiply, divide multi-digit decimals — Dividing and subtracting decimals.
  • 6.NS.B.2 Fluently divide multi-digit numbers — Using divisor times quotient plus remainder.
💡Takeaway. A quotient and a remainder together say exactly what the number was. You can always build it back.
Variant 6 medium answer: 3

A number was divided by 8.58.5 and the quotient taken only as far as its whole-number part, giving a quotient of 55 and a remainder of 3.93.9. If the same number is divided by 6.26.2 in the same way, what is the remainder?

Show solution
1 · Understandwhat's really being asked

Some number over 8.5 gives 5 remainder 3.9. Divided by 6.2 the same way, we want the new remainder.

Givens
  • Dividing by 8.5 gives quotient 5 and remainder 3.9.
  • The same number is then divided by 6.2.
  • In both cases the quotient is taken only as far as its whole-number part.
Unknowns
  • The remainder from the second division.
Constraints
  • The number itself is never stated.
2 · Planchoose the strategy

#11 Work Backwards · also uses: #7 Identify Subproblems#8 Analyze the Units

Nothing can be done with the second divisor until the number is known. Divisor times quotient plus remainder rebuilds it exactly, and then the second division is just a division.

3 · Execute3 carry out the plan

1Rebuild the number

#11 Work Backwards 6.NS.B.2
Multiply the divisor by the quotient and add the remainder.
8.5×5+3.9=46.48.5 \times 5 + 3.9 = 46.4
The number is 46.4.

2See how many 6.2s fit

#7 Identify Subproblems 6.NS.B.3
7 of them come to 43.4, and one more would overshoot.
6.2×7=43.46.2 \times 7 = 43.4
The whole-number quotient is 7.

3Take that off the number

#8 Analyze the Units 6.NS.B.3
What is left over is the remainder.
46.443.4=346.4 - 43.4 = 3
The remainder is 3.
Answer: 3
4 · Reviewdoes it hold up?

The remainder 3 is smaller than the divisor 6.2, as every remainder must be -- otherwise another whole 6.2 would have fitted.

Another way: Rebuilding from the second division instead, 6.2×7+3=46.46.2 \times 7 + 3 = 46.4, gives back the same number, which is the check that both divisions describe it.

Standardsmin grade 6
  • 6.NS.B.3 Fluently add, subtract, multiply, divide multi-digit decimals — Dividing and subtracting decimals.
  • 6.NS.B.2 Fluently divide multi-digit numbers — Using divisor times quotient plus remainder.
💡Takeaway. A quotient and a remainder together say exactly what the number was. You can always build it back.
Variant 7 medium answer: 4.5

A number was divided by 6.96.9 and the quotient taken only as far as its whole-number part, giving a quotient of 44 and a remainder of 3.33.3. If the same number is divided by 8.88.8 in the same way, what is the remainder?

Show solution
1 · Understandwhat's really being asked

Some number over 6.9 gives 4 remainder 3.3. Divided by 8.8 the same way, we want the new remainder.

Givens
  • Dividing by 6.9 gives quotient 4 and remainder 3.3.
  • The same number is then divided by 8.8.
  • In both cases the quotient is taken only as far as its whole-number part.
Unknowns
  • The remainder from the second division.
Constraints
  • The number itself is never stated.
2 · Planchoose the strategy

#11 Work Backwards · also uses: #7 Identify Subproblems#8 Analyze the Units

Nothing can be done with the second divisor until the number is known. Divisor times quotient plus remainder rebuilds it exactly, and then the second division is just a division.

3 · Execute3 carry out the plan

1Rebuild the number

#11 Work Backwards 6.NS.B.2
Multiply the divisor by the quotient and add the remainder.
6.9×4+3.3=30.96.9 \times 4 + 3.3 = 30.9
The number is 30.9.

2See how many 8.8s fit

#7 Identify Subproblems 6.NS.B.3
3 of them come to 26.4, and one more would overshoot.
8.8×3=26.48.8 \times 3 = 26.4
The whole-number quotient is 3.

3Take that off the number

#8 Analyze the Units 6.NS.B.3
What is left over is the remainder.
30.926.4=4.530.9 - 26.4 = 4.5
The remainder is 4.5.
Answer: 4.5
4 · Reviewdoes it hold up?

The remainder 4.5 is smaller than the divisor 8.8, as every remainder must be -- otherwise another whole 8.8 would have fitted.

Another way: Rebuilding from the second division instead, 8.8×3+4.5=30.98.8 \times 3 + 4.5 = 30.9, gives back the same number, which is the check that both divisions describe it.

Standardsmin grade 6
  • 6.NS.B.3 Fluently add, subtract, multiply, divide multi-digit decimals — Dividing and subtracting decimals.
  • 6.NS.B.2 Fluently divide multi-digit numbers — Using divisor times quotient plus remainder.
💡Takeaway. A quotient and a remainder together say exactly what the number was. You can always build it back.
Variant 8 medium answer: 0.6

A number was divided by 5.65.6 and the quotient taken only as far as its whole-number part, giving a quotient of 99 and a remainder of 4.14.1. If the same number is divided by 7.77.7 in the same way, what is the remainder?

Show solution
1 · Understandwhat's really being asked

Some number over 5.6 gives 9 remainder 4.1. Divided by 7.7 the same way, we want the new remainder.

Givens
  • Dividing by 5.6 gives quotient 9 and remainder 4.1.
  • The same number is then divided by 7.7.
  • In both cases the quotient is taken only as far as its whole-number part.
Unknowns
  • The remainder from the second division.
Constraints
  • The number itself is never stated.
2 · Planchoose the strategy

#11 Work Backwards · also uses: #7 Identify Subproblems#8 Analyze the Units

Nothing can be done with the second divisor until the number is known. Divisor times quotient plus remainder rebuilds it exactly, and then the second division is just a division.

3 · Execute3 carry out the plan

1Rebuild the number

#11 Work Backwards 6.NS.B.2
Multiply the divisor by the quotient and add the remainder.
5.6×9+4.1=54.55.6 \times 9 + 4.1 = 54.5
The number is 54.5.

2See how many 7.7s fit

#7 Identify Subproblems 6.NS.B.3
7 of them come to 53.9, and one more would overshoot.
7.7×7=53.97.7 \times 7 = 53.9
The whole-number quotient is 7.

3Take that off the number

#8 Analyze the Units 6.NS.B.3
What is left over is the remainder.
54.553.9=0.654.5 - 53.9 = 0.6
The remainder is 0.6.
Answer: 0.6
4 · Reviewdoes it hold up?

The remainder 0.6 is smaller than the divisor 7.7, as every remainder must be -- otherwise another whole 7.7 would have fitted.

Another way: Rebuilding from the second division instead, 7.7×7+0.6=54.57.7 \times 7 + 0.6 = 54.5, gives back the same number, which is the check that both divisions describe it.

Standardsmin grade 6
  • 6.NS.B.3 Fluently add, subtract, multiply, divide multi-digit decimals — Dividing and subtracting decimals.
  • 6.NS.B.2 Fluently divide multi-digit numbers — Using divisor times quotient plus remainder.
💡Takeaway. A quotient and a remainder together say exactly what the number was. You can always build it back.
Variant 9 hard answer: 3

A number was divided by 9.19.1 and the quotient taken only as far as its whole-number part, giving a quotient of 33 and a remainder of 4.74.7. If the same number is divided by 5.85.8 in the same way, what is the remainder?

Show solution
1 · Understandwhat's really being asked

Some number over 9.1 gives 3 remainder 4.7. Divided by 5.8 the same way, we want the new remainder.

Givens
  • Dividing by 9.1 gives quotient 3 and remainder 4.7.
  • The same number is then divided by 5.8.
  • In both cases the quotient is taken only as far as its whole-number part.
Unknowns
  • The remainder from the second division.
Constraints
  • The number itself is never stated.
2 · Planchoose the strategy

#11 Work Backwards · also uses: #7 Identify Subproblems#8 Analyze the Units

Nothing can be done with the second divisor until the number is known. Divisor times quotient plus remainder rebuilds it exactly, and then the second division is just a division.

3 · Execute3 carry out the plan

1Rebuild the number

#11 Work Backwards 6.NS.B.2
Multiply the divisor by the quotient and add the remainder.
9.1×3+4.7=329.1 \times 3 + 4.7 = 32
The number is 32.

2See how many 5.8s fit

#7 Identify Subproblems 6.NS.B.3
5 of them come to 29, and one more would overshoot.
5.8×5=295.8 \times 5 = 29
The whole-number quotient is 5.

3Take that off the number

#8 Analyze the Units 6.NS.B.3
What is left over is the remainder.
3229=332 - 29 = 3
The remainder is 3.
Answer: 3
4 · Reviewdoes it hold up?

The remainder 3 is smaller than the divisor 5.8, as every remainder must be -- otherwise another whole 5.8 would have fitted.

Another way: Rebuilding from the second division instead, 5.8×5+3=325.8 \times 5 + 3 = 32, gives back the same number, which is the check that both divisions describe it.

Standardsmin grade 6
  • 6.NS.B.3 Fluently add, subtract, multiply, divide multi-digit decimals — Dividing and subtracting decimals.
  • 6.NS.B.2 Fluently divide multi-digit numbers — Using divisor times quotient plus remainder.
💡Takeaway. A quotient and a remainder together say exactly what the number was. You can always build it back.
Variant 10 hard answer: 3.3

A number was divided by 7.87.8 and the quotient taken only as far as its whole-number part, giving a quotient of 66 and a remainder of 3.53.5. If the same number is divided by 9.49.4 in the same way, what is the remainder?

Show solution
1 · Understandwhat's really being asked

Some number over 7.8 gives 6 remainder 3.5. Divided by 9.4 the same way, we want the new remainder.

Givens
  • Dividing by 7.8 gives quotient 6 and remainder 3.5.
  • The same number is then divided by 9.4.
  • In both cases the quotient is taken only as far as its whole-number part.
Unknowns
  • The remainder from the second division.
Constraints
  • The number itself is never stated.
2 · Planchoose the strategy

#11 Work Backwards · also uses: #7 Identify Subproblems#8 Analyze the Units

Nothing can be done with the second divisor until the number is known. Divisor times quotient plus remainder rebuilds it exactly, and then the second division is just a division.

3 · Execute3 carry out the plan

1Rebuild the number

#11 Work Backwards 6.NS.B.2
Multiply the divisor by the quotient and add the remainder.
7.8×6+3.5=50.37.8 \times 6 + 3.5 = 50.3
The number is 50.3.

2See how many 9.4s fit

#7 Identify Subproblems 6.NS.B.3
5 of them come to 47, and one more would overshoot.
9.4×5=479.4 \times 5 = 47
The whole-number quotient is 5.

3Take that off the number

#8 Analyze the Units 6.NS.B.3
What is left over is the remainder.
50.347=3.350.3 - 47 = 3.3
The remainder is 3.3.
Answer: 3.3
4 · Reviewdoes it hold up?

The remainder 3.3 is smaller than the divisor 9.4, as every remainder must be -- otherwise another whole 9.4 would have fitted.

Another way: Rebuilding from the second division instead, 9.4×5+3.3=50.39.4 \times 5 + 3.3 = 50.3, gives back the same number, which is the check that both divisions describe it.

Standardsmin grade 6
  • 6.NS.B.3 Fluently add, subtract, multiply, divide multi-digit decimals — Dividing and subtracting decimals.
  • 6.NS.B.2 Fluently divide multi-digit numbers — Using divisor times quotient plus remainder.
💡Takeaway. A quotient and a remainder together say exactly what the number was. You can always build it back.
Variant 11 hard answer: 4.7

A number was divided by 6.46.4 and the quotient taken only as far as its whole-number part, giving a quotient of 55 and a remainder of 1.21.2. If the same number is divided by 9.59.5 in the same way, what is the remainder?

Show solution
1 · Understandwhat's really being asked

Some number over 6.4 gives 5 remainder 1.2. Divided by 9.5 the same way, we want the new remainder.

Givens
  • Dividing by 6.4 gives quotient 5 and remainder 1.2.
  • The same number is then divided by 9.5.
  • In both cases the quotient is taken only as far as its whole-number part.
Unknowns
  • The remainder from the second division.
Constraints
  • The number itself is never stated.
2 · Planchoose the strategy

#11 Work Backwards · also uses: #7 Identify Subproblems#8 Analyze the Units

Nothing can be done with the second divisor until the number is known. Divisor times quotient plus remainder rebuilds it exactly, and then the second division is just a division.

3 · Execute3 carry out the plan

1Rebuild the number

#11 Work Backwards 6.NS.B.2
Multiply the divisor by the quotient and add the remainder.
6.4×5+1.2=33.26.4 \times 5 + 1.2 = 33.2
The number is 33.2.

2See how many 9.5s fit

#7 Identify Subproblems 6.NS.B.3
3 of them come to 28.5, and one more would overshoot.
9.5×3=28.59.5 \times 3 = 28.5
The whole-number quotient is 3.

3Take that off the number

#8 Analyze the Units 6.NS.B.3
What is left over is the remainder.
33.228.5=4.733.2 - 28.5 = 4.7
The remainder is 4.7.
Answer: 4.7
4 · Reviewdoes it hold up?

The remainder 4.7 is smaller than the divisor 9.5, as every remainder must be -- otherwise another whole 9.5 would have fitted.

Another way: Rebuilding from the second division instead, 9.5×3+4.7=33.29.5 \times 3 + 4.7 = 33.2, gives back the same number, which is the check that both divisions describe it.

Standardsmin grade 6
  • 6.NS.B.3 Fluently add, subtract, multiply, divide multi-digit decimals — Dividing and subtracting decimals.
  • 6.NS.B.2 Fluently divide multi-digit numbers — Using divisor times quotient plus remainder.
💡Takeaway. A quotient and a remainder together say exactly what the number was. You can always build it back.
Variant 12 hard answer: 4.4

A number was divided by 9.69.6 and the quotient taken only as far as its whole-number part, giving a quotient of 22 and a remainder of 5.35.3. If the same number is divided by 6.76.7 in the same way, what is the remainder?

Show solution
1 · Understandwhat's really being asked

Some number over 9.6 gives 2 remainder 5.3. Divided by 6.7 the same way, we want the new remainder.

Givens
  • Dividing by 9.6 gives quotient 2 and remainder 5.3.
  • The same number is then divided by 6.7.
  • In both cases the quotient is taken only as far as its whole-number part.
Unknowns
  • The remainder from the second division.
Constraints
  • The number itself is never stated.
2 · Planchoose the strategy

#11 Work Backwards · also uses: #7 Identify Subproblems#8 Analyze the Units

Nothing can be done with the second divisor until the number is known. Divisor times quotient plus remainder rebuilds it exactly, and then the second division is just a division.

3 · Execute3 carry out the plan

1Rebuild the number

#11 Work Backwards 6.NS.B.2
Multiply the divisor by the quotient and add the remainder.
9.6×2+5.3=24.59.6 \times 2 + 5.3 = 24.5
The number is 24.5.

2See how many 6.7s fit

#7 Identify Subproblems 6.NS.B.3
3 of them come to 20.1, and one more would overshoot.
6.7×3=20.16.7 \times 3 = 20.1
The whole-number quotient is 3.

3Take that off the number

#8 Analyze the Units 6.NS.B.3
What is left over is the remainder.
24.520.1=4.424.5 - 20.1 = 4.4
The remainder is 4.4.
Answer: 4.4
4 · Reviewdoes it hold up?

The remainder 4.4 is smaller than the divisor 6.7, as every remainder must be -- otherwise another whole 6.7 would have fitted.

Another way: Rebuilding from the second division instead, 6.7×3+4.4=24.56.7 \times 3 + 4.4 = 24.5, gives back the same number, which is the check that both divisions describe it.

Standardsmin grade 6
  • 6.NS.B.3 Fluently add, subtract, multiply, divide multi-digit decimals — Dividing and subtracting decimals.
  • 6.NS.B.2 Fluently divide multi-digit numbers — Using divisor times quotient plus remainder.
💡Takeaway. A quotient and a remainder together say exactly what the number was. You can always build it back.