How to work out questions like these, in detail

Let the missing number be x,

For the first question, the equation is as follows,
x - 13 = 29

Solve for x,
x - 13 + 13 = 29 + 13
x = 42

The equation would then be 42 - 13 = 29

For the second question, the equation is as follows,
x - 12 = 203

Solve for x,
x - 12 + 12 = 203 + 12
x = 215

The equation would then be 215 - 12 = 203

42-13=29 and

215-12=103

Hope this helped!!!

use a calculater multiply them

2 over 9 would just be 9 x 9= 81

4 over 2 would just be 2 x 2 x 2 x 2 = 16

do NOT do 2 x 4 bec that will be 8