Beachbum don't state it like a formula that a negative number squared will give you a positive number. Explain him the logic.

Let's do it with 1

(+1) x (+1) = +1

(+1) x (-1) = -1

(-1) x (+1) = -1

(-1) x (-1) = +1

So you see that.. if you multiply a negative number 'a' to another number 'b' the resultant product 'c' has the opposite sign of 'b'.

There fore 1 x -1 x 1
can be processed as

1 x -1 = -1 which in turned multiplied by the third number 1

-1 x 1 = -1

like this you can see (-1)2 = -1 x -1 = +1

while (-1)3 = -1 x -1 x -1 = -1