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
Cardinal x multiple = multiple
Multiply ÷ radix = multiple
Multiply ÷ Multiply = radix
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
bellyband
S
zone
a
Length of side
Perimeter = side length ×
four
C=4a
zone
=
Side length × side length
S=a×
a=a
2
2
cube
Five:
roll
A:
edge
superficial area
=
Side length × side length ×
six
S
table
=a
×
a
×
6=6a
2
roll
=
Side length × side length× side length
V=a×
A x
a=a
three
three
rectangle
C
bellyband
S
zone
a
Length of side
bellyband
=(
long
+
extensive
)
×
2
C=2(a+b)
zone
=
Length × width
S=ab
four
Cubic
Five:
roll
Student:
zone
A:
long
B:
extensive
h:
high
( 1)
superficial area
(
Length × width
+
Length × height
+
Width × height
)
×
2
S=2(ab+ah+bh)
(2)
roll
=
Length× width× height
V=abh
five
triangle
s
zone
a
bottom
h
high
zone
=
Bottom× height' ao
2
s=ah
2
High triangle
=
zone
×
2
Jiandi
Triangular base
=
zone
×
2
high
six
parallelogram
s
zone
a
bottom
h
high
zone
=
Base × height
S = ah
seven
trapeziform
s
zone
a
Upper base
b
Shadi
h
high
zone
=(
Upper base
+
Shadi
)
Xigao' ao
2
s =(a+b)× 1
hú
2
eight
Round; circular
S
zone
C
bellyband
∏
d=
diameter
r=
radius
( 1)
bellyband
=
Diameter ×
∏
=2
×
∏
× radius
C=
∏
d=2
∏
r
(2)
zone
=
Radius × radius ×
∏
=
∏
r
2
nine
cylinder
Five:
roll
h:
high
s；
Jianping
r:
Bottom radius
C:
Bottom circumference
( 1)
border area/region
=
Bottom circumference × height
(2)
superficial area
=
border area/region
+
Bottom area ×
2
(3)
roll
=
Bottom area × height
(4)
Volume = lateral area.
2
× radius
10
cone
Five:
roll
h:
high
s；
Jianping
r:
Bottom radius
roll
=
Bottom area × height
three
Total number ÷ Total number of copies = average value
Sum-difference problem
(
Knowing the sum and difference of two numbers, the application problem of finding out what the two numbers are respectively.
)
Formula of
(
Sum+difference
)
÷
2
= large number
(
And poor
)
÷
2
= Decimal
Multiple summation problem (
Know the relationship between the sum of two numbers and multiples of two numbers, and find two numbers.
)
Heao
(
multiple
+ 1)
= Decimal
Decimal × multiple = large number
(
or
Sum-Decimal = large number
)
Difference problem
(Know the difference between two numbers and the multiple relation of two numbers, and find two numbers)
Chaao
(
Multiple-
1)
= Decimal
Decimal × multiple = large number
(
or
Decimal+difference = large number
)
Tree planting problem
1
The problem of planting trees on non-closed lines can be mainly divided into the following three situations.
：
(1) If trees are planted at both ends of the open line.
,
therefore
：
Number of plants = number of fragments+
1
= total length ÷ plant spacing-
1
Total length = plant spacing ×
(
Number of plants-
1)
Plant spacing = total length.
(
Number of plants-
1)
If you want to plant trees at one end of the unclosed line.
,
Don't plant trees at the other end.
,
therefore
：
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 trees are not planted at both ends of the non-closed line.
,
therefore
：
Number of plants = number of fragments-
1
= total length ÷ plant spacing-
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
The question of profit and loss
(
Profit+loss
)
Difference between two distributions = number of shares participating in distribution.
(
Daying-Xiaoying
)
Difference between two distributions = number of shares participating in distribution.
(
Big loss-small loss
)
Difference between two distributions = number of shares participating in distribution.
encounter a problem
Meeting distance = speed × meeting time
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 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
Hydrostatic velocity =
(
Downstream velocity+countercurrent velocity
)
÷
2
Current speed =
(
Downstream velocity-countercurrent velocity
)
÷
2
Concentration problem
Solute weight+solvent weight = solution weight.
Weight of solute/solution ×
100%
= concentration
Solution weight × concentration = solute weight
Solute weight-concentration = solution weight.
Profit and discount problem
Profit = selling price-cost
Profit rate = profit/cost ×
100%
=
(
Sales price/cost-
1)
×
100%
Up and down amount = principal × up and down percentage
Discount = actual selling price ÷ original selling price ×
100%(
discount
1)
Interest = principal × interest rate× time
After-tax interest = principal × interest rate× time
( 1
-Tax rate
)