Mental Subtraction Strategies

Free sample questions, a clear explanation, and 5 practice skills with an AI tutor that guides without giving the answer away.

Sample questions

1. What is 25 - 3?

✓ 22

○ 28

○ 12

○ 21

Answer: 22 — Think about counting back 3 from 25. What numbers do you say?

2. Subtract: 48 - 6

○ 40

✓ 42

○ 54

○ 41

Answer: 42 — Look at the ones place first: 8 minus 6. Then put the tens back.

3. Find the difference: 32 - 5

○ 37

○ 20

○ 33

✓ 27

Answer: 27 — Break 5 into 2 and 3. First, subtract 2 from 32 to get to 30. Then subtract the rest.

Subtract a 1-digit number from a 2-digit number mentally by counting back or using number bonds
Subtract multiples of 10 from 2-digit numbers mentally
Subtract two 2-digit numbers mentally by subtracting tens then ones, or by compensation
Use mental strategies to find the difference between numbers close to multiples of 10 or 100
Describe a situation where you would use mental subtraction to quickly figure something out, like calculating change

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