[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

Draw the numbers as lines with a certain length. Two lines add up to a bigger line/number. + always goes left to right. Minus makes you go in the opposite direction. 2x opposite results in left-to-right again.