Additive associative law: a+b+c=a+(b+c)
1
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
2
1 multiple × multiple = multiple
Multiply1Multiply = Multiply
Multiply/Multiply = 1 Multiply
three
Speed × time = distance
Distance/speed = time
Distance/time = speed
four
Unit price × quantity = total price
Total price/unit price = quantity
Total price ÷ quantity = unit price
five
Work efficiency × working hours = total workload.
Total amount of work ÷ work efficiency = working hours
Total workload ÷ working time = working efficiency
six
Appendix+Appendix = Sum
And-one addend = another addend
seven
Negative-negative = difference
Negative difference = negative
Difference+Minus = Minus
eight
Factor × factor = product
Product ÷ One factor = another factor
nine
Dividend = quotient
Dividend = divisor
Quotient × Divider = Divider
Calculation formula of mathematical graphics in primary schools
1
square
C circumference
S region
length of a side
Perimeter = side length ×4
C=4a
Area = side length × side length
S=a×a
2
cube
Five: 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
three
rectangle
C circumference
S region
length of a side
Circumference = (length+width) ×2
C=2(a+b)
Area = length × width
S=ab
four
Cubic
Five: volume
Student: Area
A: Dragon.
B:
extensive
tall
(1) Surface area (L× W+L× H+W× H) ×2
S=2(ab+ah+bh)
(2) Volume = length × width × height
V=abh
five
triangle
S region
Adidas
H height
Area = bottom × height ÷2
s=ah÷2
Height of triangle = area
× 2 base
Triangle base = area
× 2 Current height
six
parallelogram
S region
Adidas
H height
Area = bottom × height
S = ah
seven
trapeziform
S region
A shangdi
Shadi
H height
Area = (upper bottom+lower bottom) × height ÷2
s =(a+b)× 1
h \u 2
eight
Round; circular
S region
C circumference
∏
D= diameter
R= radius
(1) circumference = diameter ×∏=2×∏× radius
C=∏d=2∏r
(2) area = radius × radius×∈
nine
cylinder
Five: volume
tall
s； Jianping
R: bottom radius
C: perimeter of bottom surface
(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
Five: volume
tall
s； Jianping
R: bottom radius
Volume = bottom area × height ÷3
Total number ÷ Total number of copies = average value
Formula of sum and difference problem
(sum+difference) ÷ 2 = large number
(sum and difference) ÷ 2 = decimal
And folding problems.
Sum \ (multiple-1) = decimal
Decimal × multiple = large number
(or
And-decimal = large number)