2. Total ÷ Each copy = 4 copies.

3. Total number of copies = each copy.

4, multiple × multiple = multiple.

5, several multiples ÷ multiples = multiples.

6. Several times/multiple = multiple.

7. Speed × time = distance.

8. Distance/speed = time.

9. Distance ÷ time = speed.

10, unit price × quantity = total price.

1 1, total price/unit price = quantity.

12, total price ÷ quantity = unit price.

13, working efficiency × working time = total workload.

14, total workload ÷ working efficiency = working time.