Year 1 · Adding and Subtracting within 20 · Summary
Year 1 Adding and Subtracting within 20: summary and key words
Part of the Year 1 adding and subtracting within 20 chapter. Chapter overview · whole chapter on one page
Chapter summary
| Skill | Method |
|---|---|
| Number bonds to 20 | Take the part you know away from the whole to find the missing part. |
| Make 10 to add | Fill the first ten frame up to 10, then add what is left of the second number. |
| Doubles and near doubles | A double is two equal groups. A near double is one more or one less than a double. |
| Adding and taking away to 20 | Count on to add. Count back to take away. Zero changes nothing. |
| Finding the difference | Take the smaller number from the bigger number. |
| Missing numbers | Do the opposite. Take away to undo adding. Add to undo taking away. |
Can you…?
- I can find the missing part when I know the whole
- I can make 10 first to add
- I can work out doubles and near doubles
- I can count on to add and count back to take away, including with zero
- I can find how many more one number is than another
- I can find a missing number and solve a one-step problem
Key terms
- number bond
- two numbers that make a total
- whole
- the total, the big number in a part-whole picture
- part
- one of the numbers that makes the whole
- ten frame
- a picture with 10 boxes in two rows of five
- double
- a number added to itself, like 4 + 4
- near double
- one more or one less than a double, like 4 + 5
- difference
- how many more one number is than another
- count on
- keep going up from a number, one step at a time
- count back
- go down from a number, one step at a time
- missing number
- a number we do not know yet, shown by a box
- fact family
- four facts that use the same three numbers