Number of copies × number of copies = total number of copies

Total copies/number of copies = number of copies

Total copies/number of copies = number of copies

1 multiple × multiple = multiple

Multiply1Multiply = Multiply

Multiply/Multiply = 1 Multiply

Speed × time = distance

Distance/speed = time

Distance/time = speed

Unit price × quantity = total price

Total price/unit price = quantity

Total price ÷ quantity = unit price

Work efficiency × working hours = total workload.

Total amount of work ÷ work efficiency = working hours

Total workload ÷ working time = working efficiency

Appendix+Appendix = Sum

And-one addend = another addend

Negative-negative = difference

Negative difference = negative

Difference+negative = negative

Factor × factor = product

Product ÷ One factor = another factor

Dividend = quotient

Dividend = divisor

Quotient × Divider = Divider

Calculation formula of mathematical graphics in primary schools

square

Perimeter area side length

Perimeter = side length ×4

C=4a

Area = side length × side length

S=a×a

cube

Volume a: edge length

Surface area = side length × side length ×6

S table =a×a×6

Volume = side length × side length × side length

V=a×a×a

rectangle

Perimeter area side length

Circumference = (length+width) ×2

C=2(a+b)

Area = length × width

S=ab

Cubic

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

(1) surface area = (length× width+length× height+width× height) ×2

S=2(ab+ah+bh)

(2) Volume = length × width × height

V=abh

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

parallelogram

S area a bottom h height

Area = bottom × height

S = ah

trapeziform

Height of upper bottom b and lower bottom h in s area a

Area = (upper bottom+lower bottom) × height ÷2

s=(a+b)× h÷2

Round; circular

Area c perimeter d= diameter r= radius

(1) circumference = diameter ×∏=2×∏× radius

c =∏d = 2r

(2) area = radius × radius×∈

cylinder

V: volume h: height s; Bottom area r: bottom radius c: bottom perimeter

(1) Transverse area = bottom circumference × height.

(2) Surface area = lateral area+bottom area ×2

(3) Volume = bottom area × height

(4) Volume = lateral area ÷2× radius.

cone

V: volume h: height s; Bottom area r: bottom radius

Volume = bottom area × height ÷3

Formula of sum and difference problem;

Total number ÷ Total number of copies = average value

(sum+difference) ÷ 2 = large number

(sum and difference) ÷ 2 = decimal

And folding problems.

Sum \ (multiple-1) = decimal

Decimal × multiple = large number

(or sum-decimal = large number)

Difference problem

Difference ÷ (multiple-1) = decimal

Decimal × multiple = large number

(or decimal+difference = large number)

Tree planting problem:

1. The problem of planting trees on unclosed lines can be mainly 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

(3) If no 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)

The quantitative relationship of planting trees on the closed line is as follows:

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

Total length = plant spacing × number of plants

Plant spacing = total length/number of plants

Profit and loss issues:

(Profit+Loss) ÷ Difference between two distributions = number of shares participating in distribution.

(Big profit-small profit) ÷ Difference between two distributions = number of shares participating in distribution.

(big loss-small loss) ÷ The difference between two distributions = the number of shares participating in the distribution.

Encountered problems:

Meeting distance = speed × meeting time

Meeting time = meeting distance/speed and

Speed Sum = Meeting Distance/Meeting Time

Follow up questions:

Catch-up distance = speed difference× catch-up time

Catch-up time = catch-up distance ÷ speed difference

Speed difference = catching distance ÷ catching time

Tap water problem:

Downstream velocity = still water velocity+current velocity

Countercurrent velocity = still water velocity-current velocity

Still water velocity = (downstream velocity+countercurrent velocity) ÷2

Water velocity = (downstream velocity-countercurrent velocity) ÷2

Centralized question:

Solute weight+solvent weight = solution weight.

The weight of solute/solution × 100% = concentration.

Solution weight × concentration = solute weight

Solute weight-concentration = solution weight.

Profit and discount issues:

Profit = selling price-cost

Profit rate = profit/cost × 100% = (selling price/cost-1) × 100%.

Up and down amount = principal × up and down percentage

Discount = actual selling price ÷ original selling price× 1 00% (discount <1)

Interest = principal × interest rate× time

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