(1) Digital direct writing:

0.3+0.57=0.87 0.54÷6=0.09 2.2×5+9=20

2.4×0.5= 1.2 8-0.99=7.0 1 1.25×8÷ 1.25×8=64

0.38+0.2=0.58 2.4×0.5= 1.2 9.32-0.32+0.92=9.92

1.2×0.3÷ 1.2=0.3 4.8÷48×5=0.5 0.36÷4=0.09

(2) Vertical calculation of column: (* to be inspected) 12%

7.26×5.5 (integer product) * 4.2÷0.375=

123÷28≈(4.39) (rounded to two decimal places)

(3) Recursive equation calculation: (simple calculation required) 40%

3500÷0. 125÷8 32.4-4.8÷ 1.2×4

=3500 = 16.4

2. 1×3.6-3.6-3.6×0. 1 0. 175÷0.25×4

=3.6 =0. 175

(0.04+0.4+4)×0.25 8.74×99+8.74

= 1. 1 1 =8.74*(99+ 1)

=874

43×6.84+6.84×56+6.84 [0.3 1×8+( 1-0.74)]÷0. 1

=6.84*(43+ 1+56) =27.4

=6.84* 100

=684

(2. 1+2. 1+2. 1+2. 1)× 12.5 26.35+53.74+53.65-26.74

= 105 = 107

(4) Solve the equation:

3.4x+ 1.28 =2.3 5(2x+ 3 )=20

x=0.3 x=0.5

3x+8=4x-7 35-x=4( x+5)

x= 15 x=3

(5) Column equation, and find the solution of the equation.

1 Subtract a number 3 times from 6.7, and the difference is 2.5. Find a number.

6.7-3*x=2.5

x= 1.4

2 124 is 7 times smaller than a number. 37. What is this number?

124=7x-37

x=23

Three is four times the sum of a number and three, which is exactly six times this number. How did you find this number?

(x+3)*4=6x

x=6

fill (up) a vacancy

1) means the average height of sea level at 0 meters above sea level. If the elevation above sea level is positive, the height below sea level 155 meters in Turpan basin of Xinjiang should be recorded as (-155) meters above sea level. The elevation of Lotus Peak, the first peak in Huangshan Mountain, is 1864 meters, which should be recorded as (+1864) meters.

2) If the monthly income of a small family with 5,500 yuan is recorded as+5,500 yuan,

Then her family's hydropower and natural gas expenditure in 250 yuan this month should be recorded as (-250) yuan;

The expenditure of 25.5 yuan for small stationery should be recorded as (-25.5) yuan.

3) If the bear jumps forward 3 meters for +3 meters, then the bear jumps backward 3 meters for (-3) meters; It is still and should be recorded as (0) meters; Jumping forward 5 meters should be recorded as (+5) meters; It jumped back two meters.

Make (-2) meters.

Three. practical problem

1. There are orchids and chrysanthemums in the flower bed *** 126, most of which are 2.5 times that of chrysanthemums. How many orchids and chrysanthemums are there in the flower bed?

Put x orchids and y chrysanthemums

x+y= 126

x-y=2.5y

98 orchids and 28 chrysanthemums were obtained.

2. Warehouse A and Warehouse B store 42.5 tons of rice. Warehouse A stores 5.5 tons more rice than Warehouse B. How many tons of rice do Warehouse A and Warehouse B store respectively?

x+y=42.5

x=y+5.5

Warehouse A is 22 tons, warehouse B 16.5 tons. ..

The sum of Xiao Ming's and his father's age is 49, and his father's age is three times that of Xiao Ming and five years older. How old are Xiaoming and his father?

Xiaoming 1 1 years old, and his father is 38 years old.

4. A car and a bicycle start from A and B, with a distance of 172.5km, and walk in opposite directions. Three hours later, two cars met. The known speed is 45 kilometers per hour. What's the speed of the bike?

45*3+x*3= 172.5

x= 12.5

Bicycle speed12.5 km/h.

5. Mix goes to the Children's Palace from home, and the walking speed is 65 meters | minutes. 16 minutes later, my mother found that Mix had left a piece of material at home, so she rode her bike at the speed of 195 meters | minutes. It is understood that the distance from Jia to the Children's Palace is 1800 meters. Can Mom catch up with Mix before she reaches the Children's Palace?

Assuming mom can catch up with Mix in X minutes,

195x= 16*65+65x gives x=8.

At this time, the traveling distance of the cabinet is 65 * 24 = 1560m, which is less than 1800m.

So mom can catch up with Mix before she reaches the Children's Palace.

6. There are the same number of red and white glass balls in a bag. Take out 9 red balls and 1 1 white balls at a time. After several times, all the white balls were taken, leaving 12 red balls. How many times does a * * * shoot?

Let * * * take x times.

1 1x=9x+ 12

The solution is x=6.

* * * Take 6 times.

Exercise the brain.

There are three warehouses, A, B and C. The goods in warehouse C are half that in warehouse B, and warehouse B is 160 tons less than warehouse A, and the goods in warehouse A are four times that in warehouse C. How many tons of goods are stored in the three warehouses?

2z=y

x- 160=y

x=4z

X=320 y= 160 z=80。

A: Three warehouses * * * store 560 tons of goods.