Subtraction

What is Subtraction?

Subtraction finds the difference between two numbers, or what remains after taking one amount away from another.

Symbol: − | Result: difference

Column Subtraction with Borrowing

When a digit being subtracted is larger than the digit above it, borrow from the next column:

  742
- 385
-----
  357

2 - 5: can't do it → borrow from the tens: 12 - 5 = 7 3 (now 2) - 8: can't do it → borrow from hundreds: 12 - 8 = 4 6 (now 5) - 3 = 2 … wait, let's recount: 6 hundreds, borrow → 5 hundreds, 14 tens - 8 = 6...

Work step by step and check your answer by adding back: if 742 - 385 = 357, then 357 + 385 should = 742. ✓

Subtracting from Round Numbers

Subtracting from numbers like 1,000 requires careful borrowing:

• 1,000 - 364: think of it as 999 - 363 = 636, then it's simpler.

Mental Subtraction Strategies

• Count up: 83 - 47 → count from 47 to 83 = 36
• Round and adjust: 75 - 29 = 75 - 30 + 1 = 46

Word Problem Clues

difference, less, fewer, remain, left over, how many more, how much change