Ability to add large numbers

If you want to improve the skills of adding large numbers, then use this program. With this program, you can work on adding and subtracting numbers in a column by selecting the correct digits.
The program proposes to put the correct numbers in empty cells. Select a cell and enter the number on the screen. After completing all empty cells, check the result.
You can set the number of digits for the first and second numbers, as well as the type of operation