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+Minus = Minus

8. Factor × factor = product

Product ÷ One factor = another factor

9. Dividend bonus = quotient

Dividend = divisor

Quotient × Divider = Divider

10, total copies/total copies = average.

The formula of 1 1, sum and difference problem.

(sum+difference) ÷ 2 = large number

(sum and difference) ÷ 2 = decimal

12 and the question of time

Sum \ (multiple-1) = decimal

Decimal × multiple = large number

(or sum-decimal = large number)

13, differential time problem

Difference ÷ (multiple-1) = decimal

Decimal × multiple = large number

(or decimal+difference = large number)

14, planting trees

1 The problem of planting trees on unclosed lines can be divided into the following three situations:

(1) If trees are planted at both ends of the non-closed line, then:

Number of plants = number of nodes+1 = total length-1.

Total length = plant spacing × (number of plants-1)

Plant spacing = total length ÷ (number of plants-1)

2 If you want to plant trees at one end of the unclosed line and not at the other end, then:

Number of plants = number of segments = total length ÷ plant spacing

Total length = plant spacing × number of plants

Plant spacing = total length/number of plants

After-tax interest = principal × interest rate × time × (1-20%)