Marine arithmetic

Using the method of replacing images of numbers on examples of arithmetic operations gives a great effect of learning.
At the start of the task, the arithmetic expression with the result and the places for inserting the number is displayed. Among the proposed set of numbers, it is necessary to choose the correct variant.
You can change the settings:
- range of numbers;
- the number of tasks;
- types of operations.
The result of the execution is displayed at the end of all tasks.