From any addition fact such as
1,300 + 5,200 = 6,500
we can work out two subtraction facts.
Here we get:
6,500 – 1,300 = 5,200
and
6,500 – 5,200 = 1,300
This is handy because we can use additions to check subtractions.
Example 1
Ahmed says that
| 2,800 – 1,100 = | 1,700 |
Use addition to check if he is right or wrong.
Answer
1,700 + 1,100 = 2,800
So Ahmed is right.
Example 2
Bill says that
| 6,500 – 3,700 = | 3,200 |
Use addition to check if he is right or wrong.
Answer
3,200 + 3,700 = 6,900 not 6,500
So Bill is wrong.
