That is true because even if you used negative signs or positive signs, as long as there's a 0, you'll still get the answer of 0. About the integer chips, you won't need it. If you used 0 x (+2), that is 0 groups of 2. So then how do you draw "0" groups? You can't. For example, this can't be right:
5. Write each repeated addition as a multiplication.
a) (+1) x (+1) x (+1) x (+1) x (+1) = (+1)
b) (-6) x (-6) = 36
9. What multiplication statement does each set of diagrams represent?
(+2) x (+4) = (+8)
(+2) x (-4) = (-8)
18. Does doubling an integer always result in an integer of greater value? Explain.
Sometimes it can. If it was a negative, it would either go high or less if you saw it being represented on a number line.