1, number of copies × number of copies = total number of copies/number of copies = total number of copies/number of copies = number of copies.

2. Multiply × multiply = multiply +0 multiply = multiply +0 multiply = multiply = multiply = 1 multiply.

3. Speed× time = distance ÷ speed = time ÷ distance ÷ time = speed.

4. Unit price × quantity = total price/unit price = total quantity/quantity = unit price.

5. Work efficiency × working hours = total workload ÷ work efficiency = working hours ÷ total workload ÷ working hours = work efficiency.

6. Appendix+Appendix = sum-one addend = another addend.

7. Minus-Minus = Minus-Minus = Minus+Minus = Minus.

8. Factor × factor = product product ÷ one factor = another factor.