Sumtate app for iPhone and iPad

Math is the basis of science and arithmetic operations: +, -, *, and / are the building blocks of math.

Normally, we are given a set of numbers and want to find its sum. Sumtate reverses this arithmetic thinking. For example, given the number 7, we want to find which numbers could add up to 7. This is an example of simple logic analysis. This game uses the digits from 2 to 9. To make 7, we could use any of the following sets of numbers: {7}, {2, 5}, {3, 4}, and {2, 2, 3}.

Here is another logic analysis. If you want to win, which set should you select?