Sensim Math · Depth 한국어

← 3-1 · Ten in a place carries forward · Place-Value Regrouping

Ten in a place carries forward · 10 practice problems

2.NBT.A.13.NBT.A.2

Generated variants — 10

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

Variant 1 answer: 29

There is a three-digit number made up of 33 hundreds, 1818 tens, and 1212 ones. The number that is 200200 less than this number is made up of how many tens?

Show solution

Understand

A number is described loosely as 3 hundreds, 18 tens, and 12 ones -- the tens and ones may go past a single digit, so I first regroup to find the real number. Then I subtract 200 from it and ask how many tens make up that result.

Givens
  • The number is 3 hundreds, 18 tens, and 12 ones.
  • A second number is 200 less than this one.
Unknowns
  • How many tens make up the number that is 200 less.
Constraints
  • 10 ones regroup into 1 ten; 10 tens regroup into 1 hundred.
  • 'How many tens' means the total value divided into groups of ten.

Plan

#15 Organize Information in More Ways · also uses: #7 Identify Subproblems

The counts are written in an unusual way, so the key move is to re-organize them into standard place value by carrying. Then the task splits into clear subproblems: find the number, subtract, and re-read the answer as a count of tens.

Execute

#15 Organize Information in More Ways 2.NBT.A.1
Add up the values: 3 hundreds is 300, 18 tens is 180, and 12 ones is 12. Combine them by carrying the extra tens and ones into the next place.
300+180+12=492300 + 180 + 12 = 492
Place value lets me trade 10 ones for a ten and 10 tens for a hundred, core Grade 2 understanding of three-digit numbers.
#7 Identify Subproblems 3.NBT.A.2
Now take 200 away from 492 to get the number that is 200 less.
492−200=292492 - 200 = 292
Subtracting two three-digit numbers with regrouping is a Grade 3 fluency skill.
#15 Organize Information in More Ways 2.NBT.A.1
Read 292 as a count of tens: 292 is 29 groups of ten (with 2 ones left over).
292=29×10+2292 = 29 \times 10 + 2
Seeing 292 as 29 tens is just place-value reading.
Answer: 29

Review

Check: 29 tens = 290, and 292 + 200 = 492, which matches the original number 492, so the work is right.

Guess and check (Tool 6): a number that is 29 tens is 290; verify 290 + 2 + 200 = 492 matches the description, confirming 29 tens.

Standards · min grade 3

  • 2.NBT.A.1 Understand that the three digits of a three-digit number represent hundreds, tens, and ones — Regrouping 3 hundreds, 18 tens, 12 ones into 492 and re-reading 292 as tens.
  • 3.NBT.A.2 Fluently add and subtract within 1000 — Computing 492 - 200 = 292 with regrouping.
💡 Trade your tens and ones into neat place value, then reading the result as a count of tens is easy Grade 3 sense!
Variant 2 answer: 37

There is a three-digit number made up of 55 hundreds, 1616 tens, and 1818 ones. The number that is 300300 less than this number is made up of how many tens?

Show solution

Understand

A number is described loosely as 5 hundreds, 16 tens, and 18 ones -- the tens and ones may go past a single digit, so I first regroup to find the real number. Then I subtract 300 from it and ask how many tens make up that result.

Givens
  • The number is 5 hundreds, 16 tens, and 18 ones.
  • A second number is 300 less than this one.
Unknowns
  • How many tens make up the number that is 300 less.
Constraints
  • 10 ones regroup into 1 ten; 10 tens regroup into 1 hundred.
  • 'How many tens' means the total value divided into groups of ten.

Plan

#15 Organize Information in More Ways · also uses: #7 Identify Subproblems

The counts are written in an unusual way, so the key move is to re-organize them into standard place value by carrying. Then the task splits into clear subproblems: find the number, subtract, and re-read the answer as a count of tens.

Execute

#15 Organize Information in More Ways 2.NBT.A.1
Add up the values: 5 hundreds is 500, 16 tens is 160, and 18 ones is 18. Combine them by carrying the extra tens and ones into the next place.
500+160+18=678500 + 160 + 18 = 678
Place value lets me trade 10 ones for a ten and 10 tens for a hundred, core Grade 2 understanding of three-digit numbers.
#7 Identify Subproblems 3.NBT.A.2
Now take 300 away from 678 to get the number that is 300 less.
678−300=378678 - 300 = 378
Subtracting two three-digit numbers with regrouping is a Grade 3 fluency skill.
#15 Organize Information in More Ways 2.NBT.A.1
Read 378 as a count of tens: 378 is 37 groups of ten (with 8 ones left over).
378=37×10+8378 = 37 \times 10 + 8
Seeing 378 as 37 tens is just place-value reading.
Answer: 37

Review

Check: 37 tens = 370, and 378 + 300 = 678, which matches the original number 678, so the work is right.

Guess and check (Tool 6): a number that is 37 tens is 370; verify 370 + 8 + 300 = 678 matches the description, confirming 37 tens.

Standards · min grade 3

  • 2.NBT.A.1 Understand that the three digits of a three-digit number represent hundreds, tens, and ones — Regrouping 5 hundreds, 16 tens, 18 ones into 678 and re-reading 378 as tens.
  • 3.NBT.A.2 Fluently add and subtract within 1000 — Computing 678 - 300 = 378 with regrouping.
💡 Trade your tens and ones into neat place value, then reading the result as a count of tens is easy Grade 3 sense!
Variant 3 answer: 50

There is a three-digit number made up of 55 hundreds, 1212 tens, and 1515 ones. The number that is 130130 less than this number is made up of how many tens?

Show solution

Understand

A number is described loosely as 5 hundreds, 12 tens, and 15 ones -- the tens and ones may go past a single digit, so I first regroup to find the real number. Then I subtract 130 from it and ask how many tens make up that result.

Givens
  • The number is 5 hundreds, 12 tens, and 15 ones.
  • A second number is 130 less than this one.
Unknowns
  • How many tens make up the number that is 130 less.
Constraints
  • 10 ones regroup into 1 ten; 10 tens regroup into 1 hundred.
  • 'How many tens' means the total value divided into groups of ten.

Plan

#15 Organize Information in More Ways · also uses: #7 Identify Subproblems

The counts are written in an unusual way, so the key move is to re-organize them into standard place value by carrying. Then the task splits into clear subproblems: find the number, subtract, and re-read the answer as a count of tens.

Execute

#15 Organize Information in More Ways 2.NBT.A.1
Add up the values: 5 hundreds is 500, 12 tens is 120, and 15 ones is 15. Combine them by carrying the extra tens and ones into the next place.
500+120+15=635500 + 120 + 15 = 635
Place value lets me trade 10 ones for a ten and 10 tens for a hundred, core Grade 2 understanding of three-digit numbers.
#7 Identify Subproblems 3.NBT.A.2
Now take 130 away from 635 to get the number that is 130 less.
635−130=505635 - 130 = 505
Subtracting two three-digit numbers with regrouping is a Grade 3 fluency skill.
#15 Organize Information in More Ways 2.NBT.A.1
Read 505 as a count of tens: 505 is 50 groups of ten (with 5 ones left over).
505=50×10+5505 = 50 \times 10 + 5
Seeing 505 as 50 tens is just place-value reading.
Answer: 50

Review

Check: 50 tens = 500, and 505 + 130 = 635, which matches the original number 635, so the work is right.

Guess and check (Tool 6): a number that is 50 tens is 500; verify 500 + 5 + 130 = 635 matches the description, confirming 50 tens.

Standards · min grade 3

  • 2.NBT.A.1 Understand that the three digits of a three-digit number represent hundreds, tens, and ones — Regrouping 5 hundreds, 12 tens, 15 ones into 635 and re-reading 505 as tens.
  • 3.NBT.A.2 Fluently add and subtract within 1000 — Computing 635 - 130 = 505 with regrouping.
💡 Trade your tens and ones into neat place value, then reading the result as a count of tens is easy Grade 3 sense!
Variant 4 answer: 58

There is a three-digit number made up of 77 hundreds, 1111 tens, and 2020 ones. The number that is 250250 less than this number is made up of how many tens?

Show solution

Understand

A number is described loosely as 7 hundreds, 11 tens, and 20 ones -- the tens and ones may go past a single digit, so I first regroup to find the real number. Then I subtract 250 from it and ask how many tens make up that result.

Givens
  • The number is 7 hundreds, 11 tens, and 20 ones.
  • A second number is 250 less than this one.
Unknowns
  • How many tens make up the number that is 250 less.
Constraints
  • 10 ones regroup into 1 ten; 10 tens regroup into 1 hundred.
  • 'How many tens' means the total value divided into groups of ten.

Plan

#15 Organize Information in More Ways · also uses: #7 Identify Subproblems

The counts are written in an unusual way, so the key move is to re-organize them into standard place value by carrying. Then the task splits into clear subproblems: find the number, subtract, and re-read the answer as a count of tens.

Execute

#15 Organize Information in More Ways 2.NBT.A.1
Add up the values: 7 hundreds is 700, 11 tens is 110, and 20 ones is 20. Combine them by carrying the extra tens and ones into the next place.
700+110+20=830700 + 110 + 20 = 830
Place value lets me trade 10 ones for a ten and 10 tens for a hundred, core Grade 2 understanding of three-digit numbers.
#7 Identify Subproblems 3.NBT.A.2
Now take 250 away from 830 to get the number that is 250 less.
830−250=580830 - 250 = 580
Subtracting two three-digit numbers with regrouping is a Grade 3 fluency skill.
#15 Organize Information in More Ways 2.NBT.A.1
Read 580 as a count of tens: 580 is 58 groups of ten (with 0 ones left over).
580=58×10+0580 = 58 \times 10 + 0
Seeing 580 as 58 tens is just place-value reading.
Answer: 58

Review

Check: 58 tens = 580, and 580 + 250 = 830, which matches the original number 830, so the work is right.

Guess and check (Tool 6): a number that is 58 tens is 580; verify 580 + 0 + 250 = 830 matches the description, confirming 58 tens.

Standards · min grade 3

  • 2.NBT.A.1 Understand that the three digits of a three-digit number represent hundreds, tens, and ones — Regrouping 7 hundreds, 11 tens, 20 ones into 830 and re-reading 580 as tens.
  • 3.NBT.A.2 Fluently add and subtract within 1000 — Computing 830 - 250 = 580 with regrouping.
💡 Trade your tens and ones into neat place value, then reading the result as a count of tens is easy Grade 3 sense!
Variant 5 answer: 50

There is a three-digit number made up of 99 hundreds, 1010 tens, and 4040 ones. The number that is 540540 less than this number is made up of how many tens?

Show solution

Understand

A number is described loosely as 9 hundreds, 10 tens, and 40 ones -- the tens and ones may go past a single digit, so I first regroup to find the real number. Then I subtract 540 from it and ask how many tens make up that result.

Givens
  • The number is 9 hundreds, 10 tens, and 40 ones.
  • A second number is 540 less than this one.
Unknowns
  • How many tens make up the number that is 540 less.
Constraints
  • 10 ones regroup into 1 ten; 10 tens regroup into 1 hundred.
  • 'How many tens' means the total value divided into groups of ten.

Plan

#15 Organize Information in More Ways · also uses: #7 Identify Subproblems

The counts are written in an unusual way, so the key move is to re-organize them into standard place value by carrying. Then the task splits into clear subproblems: find the number, subtract, and re-read the answer as a count of tens.

Execute

#15 Organize Information in More Ways 2.NBT.A.1
Add up the values: 9 hundreds is 900, 10 tens is 100, and 40 ones is 40. Combine them by carrying the extra tens and ones into the next place.
900+100+40=1040900 + 100 + 40 = 1040
Place value lets me trade 10 ones for a ten and 10 tens for a hundred, core Grade 2 understanding of three-digit numbers.
#7 Identify Subproblems 3.NBT.A.2
Now take 540 away from 1040 to get the number that is 540 less.
1040−540=5001040 - 540 = 500
Subtracting two three-digit numbers with regrouping is a Grade 3 fluency skill.
#15 Organize Information in More Ways 2.NBT.A.1
Read 500 as a count of tens: 500 is 50 groups of ten (with 0 ones left over).
500=50×10+0500 = 50 \times 10 + 0
Seeing 500 as 50 tens is just place-value reading.
Answer: 50

Review

Check: 50 tens = 500, and 500 + 540 = 1040, which matches the original number 1040, so the work is right.

Guess and check (Tool 6): a number that is 50 tens is 500; verify 500 + 0 + 540 = 1040 matches the description, confirming 50 tens.

Standards · min grade 3

  • 2.NBT.A.1 Understand that the three digits of a three-digit number represent hundreds, tens, and ones — Regrouping 9 hundreds, 10 tens, 40 ones into 1040 and re-reading 500 as tens.
  • 3.NBT.A.2 Fluently add and subtract within 1000 — Computing 1040 - 540 = 500 with regrouping.
💡 Trade your tens and ones into neat place value, then reading the result as a count of tens is easy Grade 3 sense!
Variant 6 answer: 55

There is a three-digit number made up of 66 hundreds, 1212 tens, and 1616 ones. The number that is 180180 less than this number is made up of how many tens?

Show solution

Understand

A number is described loosely as 6 hundreds, 12 tens, and 16 ones -- the tens and ones may go past a single digit, so I first regroup to find the real number. Then I subtract 180 from it and ask how many tens make up that result.

Givens
  • The number is 6 hundreds, 12 tens, and 16 ones.
  • A second number is 180 less than this one.
Unknowns
  • How many tens make up the number that is 180 less.
Constraints
  • 10 ones regroup into 1 ten; 10 tens regroup into 1 hundred.
  • 'How many tens' means the total value divided into groups of ten.

Plan

#15 Organize Information in More Ways · also uses: #7 Identify Subproblems

The counts are written in an unusual way, so the key move is to re-organize them into standard place value by carrying. Then the task splits into clear subproblems: find the number, subtract, and re-read the answer as a count of tens.

Execute

#15 Organize Information in More Ways 2.NBT.A.1
Add up the values: 6 hundreds is 600, 12 tens is 120, and 16 ones is 16. Combine them by carrying the extra tens and ones into the next place.
600+120+16=736600 + 120 + 16 = 736
Place value lets me trade 10 ones for a ten and 10 tens for a hundred, core Grade 2 understanding of three-digit numbers.
#7 Identify Subproblems 3.NBT.A.2
Now take 180 away from 736 to get the number that is 180 less.
736−180=556736 - 180 = 556
Subtracting two three-digit numbers with regrouping is a Grade 3 fluency skill.
#15 Organize Information in More Ways 2.NBT.A.1
Read 556 as a count of tens: 556 is 55 groups of ten (with 6 ones left over).
556=55×10+6556 = 55 \times 10 + 6
Seeing 556 as 55 tens is just place-value reading.
Answer: 55

Review

Check: 55 tens = 550, and 556 + 180 = 736, which matches the original number 736, so the work is right.

Guess and check (Tool 6): a number that is 55 tens is 550; verify 550 + 6 + 180 = 736 matches the description, confirming 55 tens.

Standards · min grade 3

  • 2.NBT.A.1 Understand that the three digits of a three-digit number represent hundreds, tens, and ones — Regrouping 6 hundreds, 12 tens, 16 ones into 736 and re-reading 556 as tens.
  • 3.NBT.A.2 Fluently add and subtract within 1000 — Computing 736 - 180 = 556 with regrouping.
💡 Trade your tens and ones into neat place value, then reading the result as a count of tens is easy Grade 3 sense!
Variant 7 answer: 50

There is a three-digit number made up of 88 hundreds, 1414 tens, and 3030 ones. The number that is 470470 less than this number is made up of how many tens?

Show solution

Understand

A number is described loosely as 8 hundreds, 14 tens, and 30 ones -- the tens and ones may go past a single digit, so I first regroup to find the real number. Then I subtract 470 from it and ask how many tens make up that result.

Givens
  • The number is 8 hundreds, 14 tens, and 30 ones.
  • A second number is 470 less than this one.
Unknowns
  • How many tens make up the number that is 470 less.
Constraints
  • 10 ones regroup into 1 ten; 10 tens regroup into 1 hundred.
  • 'How many tens' means the total value divided into groups of ten.

Plan

#15 Organize Information in More Ways · also uses: #7 Identify Subproblems

The counts are written in an unusual way, so the key move is to re-organize them into standard place value by carrying. Then the task splits into clear subproblems: find the number, subtract, and re-read the answer as a count of tens.

Execute

#15 Organize Information in More Ways 2.NBT.A.1
Add up the values: 8 hundreds is 800, 14 tens is 140, and 30 ones is 30. Combine them by carrying the extra tens and ones into the next place.
800+140+30=970800 + 140 + 30 = 970
Place value lets me trade 10 ones for a ten and 10 tens for a hundred, core Grade 2 understanding of three-digit numbers.
#7 Identify Subproblems 3.NBT.A.2
Now take 470 away from 970 to get the number that is 470 less.
970−470=500970 - 470 = 500
Subtracting two three-digit numbers with regrouping is a Grade 3 fluency skill.
#15 Organize Information in More Ways 2.NBT.A.1
Read 500 as a count of tens: 500 is 50 groups of ten (with 0 ones left over).
500=50×10+0500 = 50 \times 10 + 0
Seeing 500 as 50 tens is just place-value reading.
Answer: 50

Review

Check: 50 tens = 500, and 500 + 470 = 970, which matches the original number 970, so the work is right.

Guess and check (Tool 6): a number that is 50 tens is 500; verify 500 + 0 + 470 = 970 matches the description, confirming 50 tens.

Standards · min grade 3

  • 2.NBT.A.1 Understand that the three digits of a three-digit number represent hundreds, tens, and ones — Regrouping 8 hundreds, 14 tens, 30 ones into 970 and re-reading 500 as tens.
  • 3.NBT.A.2 Fluently add and subtract within 1000 — Computing 970 - 470 = 500 with regrouping.
💡 Trade your tens and ones into neat place value, then reading the result as a count of tens is easy Grade 3 sense!
Variant 8 answer: 44

There is a three-digit number made up of 44 hundreds, 1515 tens, and 1010 ones. The number that is 120120 less than this number is made up of how many tens?

Show solution

Understand

A number is described loosely as 4 hundreds, 15 tens, and 10 ones -- the tens and ones may go past a single digit, so I first regroup to find the real number. Then I subtract 120 from it and ask how many tens make up that result.

Givens
  • The number is 4 hundreds, 15 tens, and 10 ones.
  • A second number is 120 less than this one.
Unknowns
  • How many tens make up the number that is 120 less.
Constraints
  • 10 ones regroup into 1 ten; 10 tens regroup into 1 hundred.
  • 'How many tens' means the total value divided into groups of ten.

Plan

#15 Organize Information in More Ways · also uses: #7 Identify Subproblems

The counts are written in an unusual way, so the key move is to re-organize them into standard place value by carrying. Then the task splits into clear subproblems: find the number, subtract, and re-read the answer as a count of tens.

Execute

#15 Organize Information in More Ways 2.NBT.A.1
Add up the values: 4 hundreds is 400, 15 tens is 150, and 10 ones is 10. Combine them by carrying the extra tens and ones into the next place.
400+150+10=560400 + 150 + 10 = 560
Place value lets me trade 10 ones for a ten and 10 tens for a hundred, core Grade 2 understanding of three-digit numbers.
#7 Identify Subproblems 3.NBT.A.2
Now take 120 away from 560 to get the number that is 120 less.
560−120=440560 - 120 = 440
Subtracting two three-digit numbers with regrouping is a Grade 3 fluency skill.
#15 Organize Information in More Ways 2.NBT.A.1
Read 440 as a count of tens: 440 is 44 groups of ten (with 0 ones left over).
440=44×10+0440 = 44 \times 10 + 0
Seeing 440 as 44 tens is just place-value reading.
Answer: 44

Review

Check: 44 tens = 440, and 440 + 120 = 560, which matches the original number 560, so the work is right.

Guess and check (Tool 6): a number that is 44 tens is 440; verify 440 + 0 + 120 = 560 matches the description, confirming 44 tens.

Standards · min grade 3

  • 2.NBT.A.1 Understand that the three digits of a three-digit number represent hundreds, tens, and ones — Regrouping 4 hundreds, 15 tens, 10 ones into 560 and re-reading 440 as tens.
  • 3.NBT.A.2 Fluently add and subtract within 1000 — Computing 560 - 120 = 440 with regrouping.
💡 Trade your tens and ones into neat place value, then reading the result as a count of tens is easy Grade 3 sense!
Variant 9 answer: 49

There is a three-digit number made up of 66 hundreds, 1313 tens, and 2424 ones. The number that is 264264 less than this number is made up of how many tens?

Show solution

Understand

A number is described loosely as 6 hundreds, 13 tens, and 24 ones -- the tens and ones may go past a single digit, so I first regroup to find the real number. Then I subtract 264 from it and ask how many tens make up that result.

Givens
  • The number is 6 hundreds, 13 tens, and 24 ones.
  • A second number is 264 less than this one.
Unknowns
  • How many tens make up the number that is 264 less.
Constraints
  • 10 ones regroup into 1 ten; 10 tens regroup into 1 hundred.
  • 'How many tens' means the total value divided into groups of ten.

Plan

#15 Organize Information in More Ways · also uses: #7 Identify Subproblems

The counts are written in an unusual way, so the key move is to re-organize them into standard place value by carrying. Then the task splits into clear subproblems: find the number, subtract, and re-read the answer as a count of tens.

Execute

#15 Organize Information in More Ways 2.NBT.A.1
Add up the values: 6 hundreds is 600, 13 tens is 130, and 24 ones is 24. Combine them by carrying the extra tens and ones into the next place.
600+130+24=754600 + 130 + 24 = 754
Place value lets me trade 10 ones for a ten and 10 tens for a hundred, core Grade 2 understanding of three-digit numbers.
#7 Identify Subproblems 3.NBT.A.2
Now take 264 away from 754 to get the number that is 264 less.
754−264=490754 - 264 = 490
Subtracting two three-digit numbers with regrouping is a Grade 3 fluency skill.
#15 Organize Information in More Ways 2.NBT.A.1
Read 490 as a count of tens: 490 is 49 groups of ten (with 0 ones left over).
490=49×10+0490 = 49 \times 10 + 0
Seeing 490 as 49 tens is just place-value reading.
Answer: 49

Review

Check: 49 tens = 490, and 490 + 264 = 754, which matches the original number 754, so the work is right.

Guess and check (Tool 6): a number that is 49 tens is 490; verify 490 + 0 + 264 = 754 matches the description, confirming 49 tens.

Standards · min grade 3

  • 2.NBT.A.1 Understand that the three digits of a three-digit number represent hundreds, tens, and ones — Regrouping 6 hundreds, 13 tens, 24 ones into 754 and re-reading 490 as tens.
  • 3.NBT.A.2 Fluently add and subtract within 1000 — Computing 754 - 264 = 490 with regrouping.
💡 Trade your tens and ones into neat place value, then reading the result as a count of tens is easy Grade 3 sense!
Variant 10 answer: 50

There is a three-digit number made up of 77 hundreds, 1313 tens, and 2222 ones. The number that is 350350 less than this number is made up of how many tens?

Show solution

Understand

A number is described loosely as 7 hundreds, 13 tens, and 22 ones -- the tens and ones may go past a single digit, so I first regroup to find the real number. Then I subtract 350 from it and ask how many tens make up that result.

Givens
  • The number is 7 hundreds, 13 tens, and 22 ones.
  • A second number is 350 less than this one.
Unknowns
  • How many tens make up the number that is 350 less.
Constraints
  • 10 ones regroup into 1 ten; 10 tens regroup into 1 hundred.
  • 'How many tens' means the total value divided into groups of ten.

Plan

#15 Organize Information in More Ways · also uses: #7 Identify Subproblems

The counts are written in an unusual way, so the key move is to re-organize them into standard place value by carrying. Then the task splits into clear subproblems: find the number, subtract, and re-read the answer as a count of tens.

Execute

#15 Organize Information in More Ways 2.NBT.A.1
Add up the values: 7 hundreds is 700, 13 tens is 130, and 22 ones is 22. Combine them by carrying the extra tens and ones into the next place.
700+130+22=852700 + 130 + 22 = 852
Place value lets me trade 10 ones for a ten and 10 tens for a hundred, core Grade 2 understanding of three-digit numbers.
#7 Identify Subproblems 3.NBT.A.2
Now take 350 away from 852 to get the number that is 350 less.
852−350=502852 - 350 = 502
Subtracting two three-digit numbers with regrouping is a Grade 3 fluency skill.
#15 Organize Information in More Ways 2.NBT.A.1
Read 502 as a count of tens: 502 is 50 groups of ten (with 2 ones left over).
502=50×10+2502 = 50 \times 10 + 2
Seeing 502 as 50 tens is just place-value reading.
Answer: 50

Review

Check: 50 tens = 500, and 502 + 350 = 852, which matches the original number 852, so the work is right.

Guess and check (Tool 6): a number that is 50 tens is 500; verify 500 + 2 + 350 = 852 matches the description, confirming 50 tens.

Standards · min grade 3

  • 2.NBT.A.1 Understand that the three digits of a three-digit number represent hundreds, tens, and ones — Regrouping 7 hundreds, 13 tens, 22 ones into 852 and re-reading 502 as tens.
  • 3.NBT.A.2 Fluently add and subtract within 1000 — Computing 852 - 350 = 502 with regrouping.
💡 Trade your tens and ones into neat place value, then reading the result as a count of tens is easy Grade 3 sense!