Question

计算下题，能简算的要简算：

1.25*2.5*0.4*8
3.7*9.5*1.6
12.13+7.15-1.13+2.85
10.8*4.2-4.2*1.8+4.2
38.5-10.5*0.8
18.6-4.62-5.38
25*3分之1*5分之2*10分之3
6分之5+7分之2+6分之1+7分之5
10.8*4.2-4.2*1.8+4.2

Answer 1

1.25X2.5X0.4X8
=(1.25x8)x(2.5x0.4)
=10x1
=10
3.7x9.5x1.6
=35.15x1.6
=56.24
12.13+7.15-1.13+2.85
=(12.13-1.13)+(7.15+2.85)
=11+10
=21
10.8*4.2-4.2*1.8+4.2
=4.2x(10.8-1.8+1)
=4.2x10
=42
38.5-10.5x0.8
=38.5-8.4
=30.1
18.6-4.62-5.38
=18.6-(4.62+5.38)
=18.6-10
=8.6
25x3分之1x5分之2x10分之3
=(25x2/5)x(1/3x3/10)
=10x1/10
=1
6分之5+7分之2+6分之1+7分之5
=(5/6+1/6)+(2/7+5/7)
=2
10.8x4.2-4.2x1.8+4.2
=4.2x(10.8-1.8+1)
=4.2x10
=42

Answer 2

1.25*2.5*0.4*8=1.25*1*8=10

3.7*9.5*1.6=.3.7*9.5*0.4*4=56.24
12.13+7.15-1.13+2.85=12.13-1.13+7.15+2.85=21
10.8*4.2-4.2*1.8+4.2=4.2*(10.8-1.8+1)=4.2*10=42
38.5-10.5*0.8=28+10.5-10.5*0.8=28+10.5(1-0.8)=28+10.5*0.2=30.1
18.6-4.62-5.38=18.6-(4.62+5.38)=18.6-10=8.6
25*1/3*2/5*3/10=1
5/6+2/7+1/6+5/7=5/6+1/6+2/7+5/7=1+1=2

10.8*4.2-4.2*1.8+4.2=4.2(10.8-1.8+1)=42

Answer 3

①1.25×8×2.5×0.4=10×1=10
②56.24
③21
④4.2×（10.8-1.8+1）=42
⑤28.1
⑥18.6-（4.62+5.38）=18.6-10=8.6
⑦四分之九
⑧二分之五
⑨4.2×（10.8-1.8+1）=42