Year 2 · Adding and subtracting · Summary
Year 2 Adding and subtracting: summary and key words
Part of the Year 2 adding and subtracting chapter. Chapter overview · whole chapter on one page
Chapter summary
| Skill | Method |
|---|---|
| Facts to 20 and related facts | Know the facts to 20. Use 3 + 4 = 7 to find 30 + 40 = 70. |
| Ones | Add or take away the ones. Keep the tens. Make a new ten if the ones go over 10. |
| Tens | Only the tens change. The ones stay the same. |
| Two two-digit numbers | Split into tens and ones. Add the tens, add the ones, then put them together. |
| Three one-digit numbers | Look for two that make 10 first. Then add the last number. |
| Order | Addition can be done in any order. Subtraction cannot. |
| Inverse and missing numbers | Check an addition by taking away. Find a missing number by doing the opposite. |
Can you…?
- I can use facts to 20 to find related facts up to 100
- I can add and take away ones and tens from a two-digit number
- I can add and subtract two two-digit numbers in columns
- I can add three one-digit numbers by making 10 first
- I know addition can be done in any order, and subtraction cannot
- I can check an answer with the inverse, and find a missing number
Key terms
- fact
- a sum or take-away we know without counting
- related facts
- facts that use the same numbers, such as 3 + 4 = 7 and 30 + 40 = 70
- inverse
- the opposite operation: take away undoes adding
- exchange
- swap 1 ten for 10 ones, or 10 ones for 1 ten
- column method
- a written sum with tens above tens and ones above ones
- missing number
- a number we do not know yet, shown by a box
- altogether
- the total, found by adding