[eli5] Trying to teach to an autistic child why 4 – (-2) is 4 +2.

Question

Title. I know it goes like that, but as an non mathematician can’t explain it to him.

In: 0

Answer 1

Try arrows? Numbers are an arrow from 0 to the number. Arrows for positive numbers go to the right, arrows for negative numbers go to the left. To add numbers you attach the 2nd arrow to the tip of the first. To subtract, you first flip the 2nd arrow around.