2x+3x=4.6

5X=4.6

X=0.92

7x-2x=6.5

5X=6.5

X= 1.3

2y+3y+6= 14.2

5Y=8.2

Y= 1.64

13x- 10x=2.7

3X=2.7

X=0.9

18x-9x= 126

9X= 126

X= 14

4y+2y=54.6

6Y=54.6

Y=9. 1

Second, list the equations and solve them.

1, 100 The wet brick weighs 450kg, and each wet brick loses weight after drying 850g. 100 how many kilograms does the wet brick weigh after drying?

850* 100=85000 (g) =85 kg

450-85=365 kg

Xiaoyu's mother is 42 years old, six times her age. How old is Xiaoyu this year?

42/6=7 years old

A calf weighs 230 kilograms, and an African elephant weighs 30 kilograms, which is more than 20 times as much. How many kilograms and tons does an African elephant weigh?

The weight of an African elephant =230*20+30=4630 (kg) =4.63 (ton).

4. Dad tied the newspaper with four ropes 1.2 meters long ... The joint was tied with a rope of 0.6 meters. How many times is the length of the rope after connection1.2m?

( 1.2*4-0.6)/ 1.2=4.2/ 1.2=3.5

5. It used to be 1 1.42 yuan. I bought a pen with 7.5 yuan yesterday, and my mother gave me 0.35 yuan today. How much money is there in the piggy bank now?

Now there is =11.42-7.5+0.35 = 3.92+0.35 = 4.27 (yuan) in the piggy bank.

6, 5 boxes of bees can brew 175 kg of honey a year. Kobayashi keeps 12 boxes of such bees. How many Jin of honey can he brew a year?

(175/5) *12 = 35 *12 = 420 (kg)

7. A store originally had 120 kg apples, but it also shipped 10 baskets of apples, each with 25 kg. How many kilograms of apples are there in the shop?

A * * * has =120+25 *10 =120+250 = 370 (kg).

8. A book has 1 16 pages. Xiaohua reads 9 pages every day. It's been seven days. How many pages are left?

Residual =116-(9 * 7) =116-63 = 53 (page)

Third, fill in one.

0.5 kg =(500) g

0.84 km =(840) m

3.95 tons = (3,950) kg

35 decimeters = 3.5 meters

75 cm =(0.75) m

506 cm =(50.6) decimeter

Fourth, judge, correctly put "√" in brackets, and wrongly put "×".

1, integer must be greater than decimal. (×)

2. The second place on the right of decimal point is percentile, and the second place on the left is percentile. (×)

3. Divide the integer "1" into 10 parts, each part is110, or it can be written as 0. 1. (√)

4. Add bricks and tiles or remove 0 after the decimal point, and the size of the decimal point remains unchanged. (×)

5,24 has no decimal point, so it cannot be expanded or reduced. (×)

6. When both sides of the equation are multiplied by the same number or divided by the same number, the equation still holds. (×)

7. The sum of the internal angles of a triangle is not necessarily equal to 180 degrees. (×)

8. Any three sticks can form a triangle. (×)