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Stage 13 of 20

Two-Digit Subtraction (No Borrow)

Learn two-digit subtraction without borrowing using place-value partitioning, left-to-right calculation, estimation, counting up, and inverse checks.

Start the interactive drill 18 checkable exercises

What You'll Learn

  • Identify subtraction problems whose corresponding columns do not require regrouping
  • Subtract tens and ones by place value rather than treating digits as labels
  • Use constant-difference and counting-up strategies where helpful
  • Verify each difference with addition and a rounded estimate

Why This Matters

Clean subtraction develops a reliable place-value model before regrouping adds complexity. It supports comparing prices, finding elapsed scores, measuring change, and determining how much remains.

The inverse check is powerful: if 95 − 62 = 33, then 62 + 33 must return 95. That connection keeps earlier addition learning active.

Understanding Two-Digit Subtraction (No Borrow)

No-borrow subtraction works cleanly when each digit in the minuend is at least as large as the matching digit below it. In 86 − 43, six ones can supply three ones and eight tens can supply four tens, so each place can be handled independently.

Partition both numbers by value: 86 is 80 + 6 and 43 is 40 + 3. Subtract 80 − 40 = 40 and 6 − 3 = 3, then combine them to make 43. This extends the place-value separation used in Stage 11, now with removal rather than combining.

Working left to right gives an early sense of scale. For 79 − 35, first calculate 70 − 30 = 40; then 9 − 5 = 4. Knowing the result will be forty-something helps you notice a misplaced digit or reversed operation.

A difference is the distance between numbers as well as an amount removed. Counting from 51 up to 74 gives 20 to reach 71 and 3 more to reach 74, so the gap is 23. This prepares the add-up strategy used when Stage 14 introduces borrowing.

Adding the same amount to both numbers preserves their distance. Thus 89 − 47 can become 92 − 50 = 42. Use this constant-difference move only when the adjusted numbers are friendlier, and always alter both numbers equally.

Worked Examples: Think It Through

Read the strategy, then prove you can use it: every example ends with a matching problem on new numbers that you answer and check right here. Answer it and press New numbers for as many fresh problems as you like.

Separate tens and ones

86 − 43

  1. 1 Subtract tens: 80 − 40 = 40.
  2. 2 Subtract ones: 6 − 3 = 3.
  3. 3 Combine 40 and 3.

86 − 43 = 43

Your turn — try it on new numbers

85 − 21 = ?

Work left to right

79 − 35

  1. 1 The tens difference is 70 − 30 = 40.
  2. 2 The ones difference is 9 − 5 = 4.
  3. 3 Join the partial differences.

79 − 35 = 44

Your turn — try it on new numbers

77 − 63 = ?

Count up to find the gap

74 − 51

  1. 1 Move from 51 to 71: that is 20.
  2. 2 Move from 71 to 74: that is 3.
  3. 3 Add the jumps: 20 + 3.

74 − 51 = 23

Your turn — try it on new numbers

78 − 17 = ?

Keep the difference constant

89 − 47

  1. 1 Add 3 to both numbers.
  2. 2 The equivalent problem is 92 − 50.
  3. 3 Subtract the friendly fifty.

89 − 47 = 42

Your turn — try it on new numbers

54 − 41 = ?

Common Mistakes and How to Fix Them

Subtracting in the wrong order

In 86 − 43, calculate 6 − 3, not 3 − 6. Read each column as top value minus bottom value.

Ignoring place value

The 8 in 86 means 80, so 8 − 4 represents 80 − 40 = 40, not merely 4.

Using no-borrow rules on an unsuitable problem

For 72 − 38, 2 cannot supply 8 ones. Do not reverse 2 − 8; recognize that Stage 14 regrouping is needed.

Two-Digit Subtraction (No Borrow) in Everyday Life

A library displayed 86 new books and lent out 43. Separating 80 − 40 and 6 − 3 shows that 43 remain. Addition confirms that 43 lent plus 43 remaining accounts for all 86.

Comparing a $79 item with a $35 item asks for the same difference, 44 dollars. Left-to-right subtraction immediately indicates a gap in the forties.

Pro Tips

  • • Check the ones digits before choosing the no-borrow method.
  • • Name values—“eighty minus forty”—instead of isolated digits.
  • • Count up when the two numbers feel easier to connect than subtract.
  • • Confirm the result by adding it to the subtrahend.

Practice Exercises

Work each problem mentally, then type the answer and check it. Nothing is marked correct until you enter a value that actually equals the result, and every problem keeps its mental-steps note in reach if you get stuck.

  1. 1. 87 − 42 = ?
  2. 2. 96 − 53 = ?
  3. 3. 78 − 24 = ?
  4. 4. 65 − 31 = ?
  5. 5. 99 − 47 = ?
  6. 6. 84 − 62 = ?
  7. 7. 76 − 35 = ?
  8. 8. 58 − 16 = ?
  9. 9. 93 − 70 = ?
  10. 10. 77 − 44 = ?
  11. 11. 69 − 28 = ?
  12. 12. 55 − 23 = ?
  13. 13. 88 − 56 = ?
  14. 14. 97 − 65 = ?
  15. 15. 64 − 22 = ?
  16. 16. 83 − 41 = ?
  17. 17. 72 − 50 = ?
  18. 18. 91 − 11 = ?

Drill Stage 13 with unlimited problems

Type your answer and press Enter. Every problem is generated on the spot and uses two-digit minus two-digit when every column stays positive. Get it wrong and the steps below show how that exact problem is solved mentally.

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Problem 1

20 − 10 = ?

Stage 13 Questions

What exactly makes a problem “no borrow”?

Every top digit is at least the corresponding bottom digit, so each place already contains enough units to subtract directly.

Can I subtract the ones before the tens?

Yes. With no regrouping the places are independent, although left-to-right work often makes the approximate size clearer.

Why does addition check subtraction?

Subtraction finds a missing addend. If 96 − 53 = 43, combining the removed 53 and remaining 43 must rebuild 96.