ArithmeticSnakes app for iPhone and iPad

The objective of the game is to place snakes on the playing field so that the circles inside them (circles are arguments of the problem) are on numbers equal to the target result. Snakes can move within the field only vertically or horizontally and cannot overlap themselves or each other. There are two types of problems — addition and subtraction, and there can be one to four problems. For example, there is an addition problem where you need to get the sum of arguments equal to 100 and you have a snake with three arguments. Place the snake on the field so that the sum of the numbers in the circles is equal to the target score, in this case 100, e.g. 25 + 25 + 50 = 100. Subtraction problems are similar to addition ones. Note that in case of subtraction, you need to subtract arguments from the initial argument marked with a spinning circle, e.g. the first argument marked by a spinning circle is 12 and the remaining two arguments are 10 and 4 — in this case, you need to do the following: 12 - 10 - 4 = -2.
The game includes over ten different settings — you can select the most appropriate difficulty.
By double tapping on any spot of the playing field not occupied by the snakes, you can set a marker which marks the spots to place the snake or you can mark the numbers which fit the arguments of the problem. There are two types of markers which can be switched by double tapping. The third double tap removes the marker from the field.