A. When you add to negative numbers, it is always negative. A positive + a positive is positive. In D, the answer is always 0. 1 + -1 is 0. In C, it varies. The bigger number not including the negative sign is the sign the number has. For example, -6 + 5 = -1. 6 is bigger than 5. You subtract the smaller number from the bigger number and that is the answer. You would then tack on the negative sign because it is -6, and 6 is bigger than 5.
Answer:
1. When he sold 20 slices of pizza at $1.25 each, he made $20
When he sold 50 slices of pizza at $1.25 each, he made $62.5
2. 96 slices of pizza. You would get that by dividing 120 by 1.25, as he needs to make $120, and each slice costs $1.25
