Subtracting multiples of 10 and 100

Subtracting tens is like subtracting ones: 7 tens − 3 tens = 4 tens, so 70 − 30 = 40. Here is how to take away 10, 100 and more.

The big idea: count tens like ones

A multiple of 10 is 10, 20, 30, 40 and so on. Each is a number of tens: 70 is 7 tens. So subtracting multiples of 10 uses facts your child already knows.

This is why the facts within 20 matter so much: every subtraction fact is reused for tens and hundreds.

See it: pictures to draw with your child

Copy these onto paper or a whiteboard. A quick sketch makes the idea concrete before any written method.

4050607080−10−10−107444
74 − 30: three jumps back of 10. 64, 54, 44.
70 − 30: take away 3 of the 7 tens
7 tens take away 3 tens leaves 4 tens: 70 − 30 = 40.
800 − 300
8 hundreds take away 3 hundreds leaves 5 hundreds.

Ten less and a hundred less

When you take away 10, only the tens digit changes: it goes down by 1. 57 − 10 = 47, and the ones digit (7) stays the same.

When you take away 100, only the hundreds digit goes down by 1. 462 − 100 = 362.

On a hundred chart, taking away 10 moves you straight up one row. Ask your child to put a finger on 83, then move up: 73, 63, 53. “What changes? What stays the same?”

Watch the edge case: 105 − 10 = 95. The tens digit was 0, so one hundred is traded for ten tens first. Children who write 195 need to see this on a number line.

Jump back in tens

Set the start and how much to take away. Blue arcs are jumps of 10, red arcs are ones.

Taking tens from any number

To take a multiple of 10 from a 2-digit number, take away from the tens and leave the ones alone. 74 − 30: 7 tens − 3 tens = 4 tens, and the 4 ones stay. Answer: 44.

On a number line, that is three jumps back of 10: 64, 54, 44.

The same works for hundreds: 645 − 300 = 345. Only the hundreds digit changes.

Using tens to subtract any 2-digit number

Taking away tens is the first half of most mental subtraction. For 74 − 36, take away the tens first: 74 − 30 = 44. Then take away the ones: 44 − 6 = 38. This is the jump strategy, and it depends on taking away tens quickly.

A second trick is taking away 9 or 11. To take away 9, take away 10 and add 1 back: 46 − 9 = 36 + 1 = 37. To take away 11, take away 10 and 1 more: 46 − 11 = 35. The same idea works for 19, 21, 29 and 31.

Patterns to spot

Ones factTensHundreds
5 − 2 = 350 − 20 = 30500 − 200 = 300
9 − 4 = 590 − 40 = 50900 − 400 = 500
13 − 6 = 7130 − 60 = 701,300 − 600 = 700
10 − 7 = 3100 − 70 = 301,000 − 700 = 300

Each row uses one fact three times. The last row uses the pairs that make 10, which also give the pairs that make 100 and 1,000.

Quiz: take away tens and hundreds

Use the fact you know, then put the tens or hundreds back.

Where this fits: subtraction step by step

  1. What is subtraction
  2. Subtraction within 10
  3. Counting back
  4. Subtraction on a number line
  5. Counting up
  6. Fact families
  7. Make 10 subtraction strategy
  8. Subtraction within 20
  9. Subtracting tens and hundreds (this page)
  10. 2-digit subtraction
  11. Subtraction with regrouping
  12. 3-digit subtraction
  13. Subtracting across zeros
  14. Mental subtraction strategies
  15. Checking subtraction with addition
  16. Missing number subtraction
  17. Estimating differences
  18. Multi-digit subtraction
  19. Subtraction word problems

What to say to your child

A short script for teaching it the first time. Pause after each line and let your child do the next step.

  1. “What is 7 − 3?” (4.) “So what is 7 tens − 3 tens?” (4 tens!)
  2. “And 4 tens is…?” (40.) “So 70 − 30 = 40.”
  3. “Now 57 − 10. Only one digit changes. Which one?” (The tens: 47.)
  4. “Let’s try 74 − 30. Jump back 10 three times.” (64, 54, 44.)
  5. “And 800 − 300?” (8 − 3 = 5, so 500.)

More worked examples

Example 1: tens: 90 − 60

9 − 6 = 3, so 9 tens − 6 tens = 3 tens = 30.

Example 2: tens from a 2-digit number: 86 − 50

8 tens − 5 tens = 3 tens. The 6 ones stay. Answer: 36.

Example 3: crossing 100: 130 − 50

13 tens − 5 tens = 8 tens = 80.

Example 4: hundreds: 750 − 300

7 hundreds − 3 hundreds = 4 hundreds. The 50 stays. Answer: 450.

Practice questions (answers below)

Ask these out loud or write them down. Check each answer, and ask “how did you get that?” for one or two.

  1. 80 − 30
  2. 60 − 60
  3. 100 − 40
  4. 67 − 10
  5. 94 − 30
  6. 105 − 10
  7. 900 − 600
  8. 538 − 100
  9. Raj had 70 stickers and gave away 20. How many are left?
  10. Stretch: 640 − 50 − 200
Show the answers
  1. 50
  2. 0
  3. 60
  4. 57
  5. 64
  6. 95
  7. 300
  8. 438
  9. 50 stickers
  10. 390

Common mistakes

Taking away from the ones as well74 − 30 = 41, because they take 3 from the ones too.Fix: only the tens change: 7 tens − 3 tens = 4 tens, so 44.
Losing a zero90 − 60 = 3.Fix: say it in tens: 9 tens − 6 tens = 3 tens, which is 30.
Writing 195 for 105 − 10Thinks the tens digit is 0, so it cannot go down.Fix: trade 1 hundred for 10 tens: 10 tens − 1 ten = 9 tens, so 95.

How to teach it at home

Hundred chart climb

Point to a number and move up a row to take away 10.

Coins and notes

Pay with 10-rupee notes or dimes and work out what is left in your head.

Count back by 10s

Count back by 10 from any number: 87, 77, 67… while walking or on the stairs.

By grade

More for each grade: Grade 1 math and the CBSE class 1 maths guide; Grade 2 math and the CBSE class 2 maths guide; Grade 3 math and the CBSE class 3 maths guide.

Worksheets and practice

2-digit subtraction worksheet, page 1

2-digit subtraction worksheet: printable PDF with an answer key. · Make a fresh test

Subtraction practice · subtraction speed test · subtraction chart · subtraction for kids · Multiplication practice trainer · 1-minute speed test

Last reviewed

Questions parents ask

How do you subtract multiples of 10?

Use the ones fact and keep the tens. 70 − 30: 7 − 3 = 4, so 7 tens − 3 tens = 4 tens, which is 40.

What is 10 less than a number?

Take 1 away from the tens digit and keep the ones digit. 10 less than 64 is 54. 10 less than 105 is 95.

How do you subtract 100 from a number?

Take 1 away from the hundreds digit. 462 − 100 = 362. The tens and ones stay the same.

What grade learns subtracting multiples of 10?

Grade 1 subtracts multiples of 10 within 100 (1.NBT.C.6). Grade 2 takes 10 or 100 from 3-digit numbers mentally (2.NBT.B.8).

Why is subtracting tens important?

It is the first step in mental subtraction. To work out 74 − 36 in your head, take 30 first (44) and then 6 (38).