I. Basic issues
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 hours = total workload ÷ work efficiency = working hours ÷ total workload ÷ working hours = work efficiency.
6. Appendix+Appendix = sum- 1 addend = another 1 addend.
7. Minus-Minus = Minus-Minus = Minus+Minus = Minus
8. Factor × factor = product present 1 factor = another1factor.
9. Dividend = quotient dividend = divisor quotient × divisor = dividend
Two. Calculation formula of mathematical graphics in primary schools
1, squared
Perimeter area side length
Perimeter = side length ×4 C=4a
Area = side length × side length S=a×a
2. Cubic
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.
3. rectangular
Perimeter area side length
Circumference = (length+width) ×2 C=2(a+b)
Area = length × width S=ab
4. Cuboid
V: volume s: area a: length b: width h: height.
(1) surface area (length× width+length× height+width× height )× 2s = 2 (AB+ah+BH)
(2) volume = length× width× height V=abh
5. 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
6. Parallelogram
S area a bottom h height
Area = bottom × height s=ah
7. trapezoidal
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.
8, round
Area c perimeter d= diameter r= radius
(1) perimeter = diameter ×∏=2×∏× radius C=∏d=2∏r
(2) area = radius × radius×∈
9. Cylinder
V: volume h: height s; Bottom area r: bottom radius c: bottom perimeter
(1) lateral area = bottom circumference × height.
(2) Surface area = lateral area+bottom area ×2
(3) Volume = bottom area × height
(4) Volume = lateral area ÷2× radius.
10 cone
V: volume h: height s; Bottom area r: bottom radius
Volume = bottom area × height ÷3
Total number ÷ Total number of copies = average value
Three. Formula of sum and difference problem
(sum+difference) ÷ 2 = large number
(sum and difference) ÷ 2 = decimal
Four. And folding problems.
Sum \ (multiple+1) = decimal.
Decimal × multiple = large number
(or sum-decimal = large number)
Five. Difference problem
Difference ÷ (multiple-1) = decimal
Decimal × multiple = large number
(or decimal+difference = large number)
Six. 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)
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
Plant spacing = total length/number of plants
Seven. 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.
Eight. encounter a problem
Meeting distance = speed × meeting time
Meeting time = meeting distance/speed and
Speed Sum = Meeting Distance/Meeting Time
Nine. Catch up with the problem
Catch-up distance = speed difference× catch-up time
Catch-up time = catch-up distance ÷ speed difference
Speed difference = catching distance ÷ catching time
With Tenuto 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
Eleven. Concentration problem
Solute weight+solvent weight = solution weight.
The weight of solute/solution × 100% = concentration.
Solution weight × concentration = solute weight
Solute weight-concentration = solution weight.
Twelve. 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× time
After-tax interest = principal × interest rate × time × (1-20%)
Profit 1* quantity 1+ profit 2* quantity 2= total profit.
Thirteen. Length unit conversion
1 km =1000m1m =1decimeter/decimeter =10cm1m =10cm/kloc-.
Fourteen regional 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
Fifteen. Volume (volume) unit conversion
1 m3 = 1000 m3 1 m3 = 1000 cm3 1 m3 = 1 liter 1 m3 = 1 ml/kloc-.
Sixteen years old. Weight unit conversion
1t = 1000kg 1kg = 1000g 1kg = 1kg。
Seventeen. arithmetic series
Sum of series = (first item+last item) × number of items ÷2
The last term = the first term+(number of terms-1) × tolerance.
Number of items = (last item-first item) ÷ tolerance+1