Mathematical formula about quantity
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, 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
On the calculation formula of mathematical graphics
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) ×2
S=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 perimeter π diameter r radius
(1) circumference = diameter ×π=2×π× radius
C=πd=2πr
(2) Area = radius × radius× π
9. Cylinder
V: volume h: height s: bottom area r: bottom radius c: bottom circumference.
(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, conical
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. If trees are planted at both ends of the unclosed 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)