1, number of copies × number of copies = total number of copies/number of copies = total number of copies/number of copies = number of copies.
2. 1 multiple× multiple = multiple1multiple = multiple/multiple = 1 multiple
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 time = total workload.
Total amount of work ÷ work efficiency = working hours
Total workload ÷ working time = working efficiency
6. Appendix+Appendix = sum, and-one addend = another addend.
7. Minus-Minus = Minus-Minus = Minus+Minus = Minus
8. Factor × factor = product ÷ one factor = another factor.
9. Dividend = quotient dividend = divisor quotient × divisor = dividend
Calculation formula of mathematical graphics in primary schools
1, square c perimeter s area a side length perimeter = side length× 4c = 4a area = side length× side length s = a× a.
2. rectangle c perimeter s area a side length perimeter = (length+width) ×2 C=2(a+b) area = length × width S=ab.
3, triangle S area A base H height area = base × height ÷2 s=ah÷2
Height of triangle = area ×2÷ base of triangle = area ×2÷ height
4. parallelogram s area a base h height area = base x height s=ah
5. Trapezoidal S area A upper bottom B lower bottom H height area = (upper bottom+lower bottom) × height ÷2 s=(a+b)× h÷2.
6, circular S area C perimeter ∏ d= diameter r= radius
(1) perimeter = diameter ×∏=2×∏× radius C=∏d=2∏r (2) area = radius× radius× ∏.
7. Total number of copies = average total number of copies
Formula of sum and difference problem
(sum+difference) ÷ 2 = large number (sum-difference) ÷ 2 = decimal.
And folding problems.
Sum ÷ (multiple-1) = decimal × multiple = large number (or sum-decimal = large number)
Difference problem
Difference ÷ (multiple-1) = 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 = 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)
2. 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 = total length ÷ number of plants
The question of profit and loss
(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.
encounter a problem
Meeting distance = speed and x meeting time = meeting distance ÷ speed and
Speed Sum = Meeting Distance/Meeting Time
Catch up with the problem
Catch-up distance = speed difference × catch-up time = catch-up distance/speed difference
Speed difference = catching distance ÷ catching time
Tap water problem
Downstream velocity = still water velocity+flow velocity = still water velocity-flow velocity
Still water speed = (downstream speed+countercurrent speed) ÷2 Water flow speed = (downstream speed-countercurrent speed) ÷2
Concentration problem
Solute weight+solvent weight = solution weight/solution weight × 100% = concentration.
Solution weight × concentration = solute weight/solute concentration = solution weight.
Profit and discount problem
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 × after-tax time interest = principal × interest rate × time × (1-20%)
Length unit conversion
1 km =1000m1m =1decimeter/decimeter =10cm1m =10cm/kloc-.
Area unit conversion
1 square kilometer = 100 hectare 1 hectare = 10000 square meter 1 square meter = 100 square decimeter.
1 dm2 = 100 cm2 1 cm2 = 100 mm2
Volume (volume) unit conversion
1 m3 = 1000 cubic decimeter 1 cubic decimeter = 1000 cubic centimeter 1 cubic decimeter = 1 liter.
1 cm3 = 1 ml 1 m3 = 1000 liter
Weight unit conversion
1t = 1000kg 1kg = 1000g 1kg = 1kg。