Add within 1000: Level 2

The first instance of the  exercise is in the Early Math Math Mission. This exercise helps users to learn to add numbers in the hundreds.

Types of Problems
There is only one type of problem in this exercise:
 * 1) Adding numbers in the hundreds: This type of exercise asks users to identify the ones, tens or hundreds in a large number in order to add a slightly smaller to it.

Strategies
These problems are simple once you get the hang of them!
 * 1) Just identify the ones, tens or hundreds in the empty box while adding. Remember to carry over, if necessary!
 * 2) It seems as if the empty box is sort of like a prompt: in that box goes one of the only values in the problem that change.