Touch Integers ℤ (+ - × ÷)
Is very easy add and subtract graphically. One can regroup the tokens of each order, regroup, carry or borrow tokens, and you can obtain the result
But not so easy to practice multiplication or division in this visual and interactive way
I looked the inside of the numbers:
Inside the numbers there are the components of the number: The prime factors.
To multiplicate two integers you must regroup the components of the two numbers.
To divide a integer, you must separate the components.
The program only works with integers. adds, subtract, multiplies and divides (but only exact division)