1, number of copies × number of copies = total

Total copies/number of copies = number of copies

Total copies/number of copies = number of copies

2, 1 multiple× multiple = multiple

Multiply1Multiply = Multiply

Multiply/Multiply = 1 Multiply

3. Speed × time = distance

Distance/speed = time

Distance/time = speed

4. Unit price × quantity = total price

Total price/unit price = quantity

Total price ÷ quantity = unit price

5. Work efficiency × working time = total workload.

Total amount of work ÷ work efficiency = working hours

Total workload ÷ working time = working efficiency

6. Appendix+Appendix = Total

And-one addend = another addend

7. Negative-negative = difference

Negative difference = negative

Difference+negative = negative

8. Factor × factor = product

Product ÷ One factor = another factor

9. Dividend bonus = quotient

Dividend = divisor

Quotient × Divider = Divider

10, square

C perimeter, s area, a side length

Perimeter = side length ×4

C=4a

Area = side length × side length

S=a×a

1 1, cube

V: volume, a: side length

Surface area = side length × side length ×6

S table = a× a× 6

Volume = side length × side length × side length

V=a×a×a

12, rectangle

C perimeter, s area, a side length

Circumference = (length+width) ×2

C=2(a+b)

Area = length × width

S=ab

13, cuboid

V: volume, s: area, a: length, b: width and h: height.

Surface area (length× width+length× height+width× height) ×2

S=2(ab+ah+bh)

Volume = length× width× height

V=abh

14, triangle

S area, a bottom, h height

Area = bottom × height ÷2

s=ah÷2

Height of triangle = area ×2÷ base.

Triangle base = area ×2÷ height