The first page:
I. 31.2,8.7, 1.26,12,4
17,0.4, 0.24, 3 , 0.06, 15
Two. 4. 14, 0. 144, 2.04, 28
Three. 16.25, 162.5, 0. 1625,42, 0.42, 0.42.
Four. 15.6, 27.72
Page two:
Four. 2.25, 4. 16, 25.75, 82
Verb (abbreviation of verb) 4.8×3.2÷2 2.8× 1.6
= 15.36÷2 =4.48 (square centimeter)
=7.68 (square centimeter)
(2.4+4.6)×3.2÷2(8.4+ 1 1.8)×7.5÷2
=7×3.2÷2=20.2×7.5÷2
= 1 1.2 (square centimeter) =75.75 (square centimeter)
Page three:
Sixth, solve the problem.
1, 680 ÷ 4× 3.2 =170× 3.2 = 544km.
2. ① 541.8÷15 = 36.12 (m)
② 54 1.8÷7= 77.4 (m)
③ 77.4-36.12 = 41.28 (m)
3. 185×5.4= 999 km
4.0.8× 24×18 =19.2×18 = 345.6 (yuan)
Page four:
5.324×1.2+48 = 388.8+48 = 436.8 (yuan)
Improved articles:
1、28
2、 392.6× 192-39260×0.927.5×23+3 1×2.5
=392.6× 192-392.6×92=2.5×(3×23)+3 1×2.5
=392.6×( 192-92)=2.5×(69+3 1)
=392.6× 100 =2.5× 100
=39260=250
3、 0.79×0.46+7.9×0.24+ 1 1.4×0.079
=0.79×0.46+0.79×2.4+ 1. 14×0.79
=0.79×(0.46+2.4+ 1. 14)
=0.79×4
=3. 16
Page five:
1 、>; ，& lt，& lt，& lt，& gt，& gt
2、32.37.7
3、0.832.46
4、0.56× 10 1 =0.56× 100+0.56× 1=56+0.56=56.56
2.37×0.5×4=2.37×(0.5×4)=2.37×2=4.74
3.7×2.5+6.3×2.5=(3.7+6.3)×2.5= 10×2.5=25
1.2×0.25=4×0.25×0.3= 1×0.3=0.3
0.25×6.9×0.4=0.25×0.4×6.9=0. 1×6.9=0.69
0.25×32× 1.25=0.25×4×(8× 1.25)= 1× 10= 10
Page six:
5. Perimeter (4.8+3.2)×2=8×2= 16 (cm)
Area 4.8×3= 14.4 (square centimeter)
6, 1) 4.75× 1.2=5.7 (yuan)
2) Length 6×1.5 = 9m× 6 = 54m 2.
Or 6× 1.5×6=9×6=54 (square meter)
3) (35.7+24.3) × 25 = 60× 25 =1500 (yuan)
Page seven:
4)15× 0.45 = 6.75km 6× 0.9 = 5.4km.
6.75 & gt5.4
A: Teacher Li's home is 6.75 kilometers away from school, so it takes 0.9 hours to get to school.
5) 2.94× 23 = 67.62m ≈ 68m
6) 6.5× 4 ÷ 2 ÷100×12 = 0.13×12 =14.
Page 8:
7)24× 18.5=444 (square centimeter)
8)4.8× 1.5÷2=7.2÷2=3.6 (square centimeter)
(2.7+6.3)×5÷2=45÷2=22.5 (square decimeter)
9)10× 20+(12-10 )× (20-14) ÷ 2 = 200+6 = 206 (square centimeter) (various methods).