Question

Fill in the blank to make the number sentence TRUE.

1. 43 +Blank = 53 + 19

2. 22 + 38 =Blank + 36


3. 90 + 10 = 150 - blank


4. 101 + 68 = 100+

Answer 1

1. 29

2. 24

3. 50

4. 69

Explanation:

You can replace blank with x, and isolate x for each equation by moving the numbers on the same side of the x to the other side by subtracting them.

For example, for 1.

`43+x=53+19\\43-43+x=72-43 \\\\x=29`

subtract 43 by both sides to move it to right