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.