PathSums is a numeric puzzle game
You are presented with a grid of numbers and operations, a starting point and a goal total
The object is to move up, down, left or right from square to square trying to reach the target value
Each operation is carried out on the total as you go, so 3 + 1 x 5 would be 20, not 8
The total can't go below 1 or above 100, and divisions which would lead to fractions are not allowed.
All puzzles given can be completed within these rules.

You can select board size (4x4 or 6x6), difficulty (1 to 8), and normal or expert mode.
In normal mode the total is shown as you go.
In expert mode the total is only shown when you have created your path and tap the ? at the top - at that point the game determines whether you are right or wrong; if you did something illegal (according to the rules above) the total will show 'e' and the game will highlight the value that caused the problem.
Difficulty determines the minimum number of numbers required to solve each puzzle.

At any point you can select Solve to show a solution, although you will fail that puzzle.
If you solve a puzzle and the game can solve it in fewer steps it shows you the shorter path!