Question

Mr. Lin writes the expressions

-20 - 8 and 8 - (-20) on the board.
He asks his class which result is greater. How can his class decide without finding
the value of each difference?

Answer 1

The first one will be all negative and the second one will be all positive

Answer 2

Just see that the first expression has all negative, meaning the total will be a negative, but the second expression the subtraction sign and the negative sign are together, there's a rule when two negative sign's are together/next to each other, they turn into a addition sign, so it basically 8 + 20 for the second expression, so 8-(-20) has a higher result

Explanation:

There's no work needed to be done :P