Question

When adding 51.2 to a certain number, the sum is 56.05, as seen below. What number should go in the box to complete the addition problem?

Answer 1

I know this is already answered but I need points-

two digits to the right you have to carry one, and 1+1+x = 6 so 2+x=6, so x=4

Explanation:

Thanks for the points-

Answer 2

You have a setup that will look similar to this:
51.2 + x = 56.05
x = 56.05 - 51.2
x = 4.85

The number that is the missing box is 4