Step-by-step Maths Level 5 · Adding and subtracting whole numbers to a million · Summary
Step-by-step Maths Level 5 Adding and subtracting whole numbers to a million: summary and key words
Part of the Step-by-step Maths Level 5 adding and subtracting whole numbers to a million chapter. Chapter overview · whole chapter on one page
Chapter summary
| Skill | Method |
|---|---|
| Column addition | Add from the right; carry the ten into the next column |
| Column subtraction | Exchange 1 from the left when the top digit is smaller; across zeros, make each zero a 9 |
| Estimating | Round each number to the nearest 10,000, then calculate |
| Checking | Subtract to check a sum; add back to check a difference |
| Missing numbers | Use the inverse: subtract to find an addend, add to find a number taken away |
| Two-step problems | Work out the first step, then use the answer for the next |
Can you…?
- I can add two numbers with up to six digits, carrying in several columns
- I can subtract in columns, exchanging across zeros
- I can estimate by rounding first
- I can check a sum by subtraction and a difference by addition
- I can find a missing number in a sum or difference
- I can solve two-step problems with numbers to a million
Key terms
- carry
- move a ten from one column to the column on its left
- exchange
- swap 1 from one column for 10 in the column on its right
- estimate
- a rough answer, found by rounding first
- inverse
- the operation that undoes another; subtraction undoes addition