Adding and taking away within 18 · Usually met around P1
Zero
+ 0 or − 0: no change. Minus itself: 0.
How to do it
Method
+ 0 or − 0: no change. Minus itself: 0
4 + 0 = 4, 4 − 0 = 4, 4 − 4 = 0
Another way
Number line
+ 0: stay on 4
In full
0 means none at all. Adding 0 or taking away 0 leaves a number as it is: 4 + 0 = 4 and 4 − 0 = 4, since nothing is added and nothing taken. A number take away itself leaves nothing: 4 − 4 = 0. Or look at a number line: adding 0 or taking away 0 means not moving at all.
Worked examples
Have a go first, then open each one for the answer and the working.
Example 1
0 + 18 = □
Show the answer and working
Answer: 18
Adding 0 adds nothing, so the answer stays 18.
Example 2
□ − 3 = 0
Show the answer and working
Answer: 3
Taking 3 leaves none, so there were exactly 3.
Example 3
Which of these comes to 0?
- A. 1 + 0
- B. 16 − 0
- C. 0 + 16
- D. 16 − 16
Choose the right answer
Show the answer and working
Answer: D. 16 − 16
A number take away itself leaves none: 16 − 16 = 0.
Practise it in the game →Adding and taking away within 18 · Free to start, unlimited questions, no download