Open navigation menu
Mathematics
Addition and subtraction with regrouping — Trade one ten for ten ones
Loading resource…
Loading resource…
Group and exchange hundreds, tens and ones, and follow each step in the column calculation.
There are only 2 ones; we need 7. Exchange 1 ten for 10 ones.
| Hundreds | Tens | Ones | |
|---|---|---|---|
| 4 | 2 | ||
| − | 1 | 7 | |
4 tens + 2 ones
Value on the board42
There are only 2 ones; we need 7. Exchange 1 ten for 10 ones.
Preparing the resourceModel notes
- This resource uses whole numbers from 0 to 999. Addition must have a sum no greater than 999; subtraction must have a non-negative result.
- One ten equals ten ones; one hundred equals ten tens. Grouping and exchanging preserve value. Blocks are counting tools; the area of compact groups is not a value scale.
- Subtraction is shown by regrouping the starting number. Do not combine this method with adding a borrowed amount to the subtrahend.
- Examples with two adjacent exchanges are extensions of the tool, not standard requirements for grades 2 or 3. The resource does not cover the entire curriculum of either grade.