1、3 20 12

2,811or 4 1 2 or 4 2 1

3、24 8

4、400 6

5、 1000 100

6、64 72

7、48 24

8、5

9.1.02m3 =( 1020) cubic decimeter =( 1020) liter

470 ml =(470) ml =(0.47) l.

10, a bottle of ink is about 50 (ml), and the volume of a goldfish bowl is about 38 (cubic decimeter).

The cover of a math textbook is about 280 (square centimeter), and the volume of a refrigerator is 1.5 (cubic meter).

1 1、32 136 96

36 2 16 2 16

12、 1000 3

13、60 66

Second, multiple choice questions

1、B 2、C 3、B 4、C 5、B 6、A 7、A 8、A

Third, the operation questions

1, omitted

2、6a2 10a2 14a2 22a2

3.30×2+20×2+25×4+25=225 (cm) 225 cm =22.5 decimeter.

Fourth, solve the problem.

1, (12+8+5)×4= 100 (cm)

(12× 8+8× 5+12× 5) × 2 = 392 (square centimeter).

2.18×13× 25÷50 =117 (cubic centimeter)

24÷4=6 (decimeter) 6×6×6=2 16 (cubic decimeter)

2 16 cubic decimeter =2 16 liter

6×6×5= 180 (square decimeter)

4,2800 (10×10) = 28 (cm)

5.4×3.5×2=28 (cubic decimeter) 28×4.5= 126 (kg)

6240 liters =240 cubic decimeters

240( 10×6)= 4 (decimeter)

15× 12= 180 (m2)

(15× 4+12× 4 )× 2+180 = 396 (square meter) 396-20=376 (square meter)

8.10×10× (6-3.2) =280 (cubic decimeter) 280 cubic decimeter = 280 liters

9.( 1) 10×0.4×8=32 (square meter)

(2) 10×0.3×8+32=56 (square meter)

Fifth, thinking expansion.

(15× 7+7×11+15×1) × 2× 3 = 2082 (square centimeter)

Maximum value: 2082-7×11× 4 =1774 (square centimeter)

Minimum value: 2082-15×1× 4 =1422 (square centimeter)