Question

简便方法计算：（1/10+1/18+1/30）×45/7 急~~~

还有：383 3/4×7.9+79×61 5/8 和 0.125×2 3/4+1/8×6.25-12.5%

Answer 1

(1)（1/10+1/18+1/30）×45x7
=（9/90+5/90+3/90)*45/7
=(17/90*45/7
=17/14

(2)383 3x4×7.9+79×61 5/8
=(383+3x4)*(8-0.1)+(80-1) *5x8
=3064-38.3+6-0.075+50-0.625
=3081

(3)0.125×2 3x4+1/8×6.25-12.5%
=0.125×2 3x4+0.125×6.25-0.125
=0.125*(5.75+6.25-1)
=0.125*11
=1.375
可以吗？

Answer 2

（1/10+1/18+1/30）×45/7
=（9/90+5/90+3/90)*45/7
=(17/90*45/7
=17/14
383 3/4×7.9+79×61 5/8
=(383+3/4)*(8-0.1)+(80-1) *5/8
=3064-38.3+6-0.075+50-0.625
=3081
0.125×2 3/4+1/8×6.25-12.5%
=0.125×2 3/4+0.125×6.25-0.125
=0.125*(5.75+6.25-1)
=0.125*11
=1.375

Answer 3

383 3/4×7.9+79×61 5/8 =383 3/4*7.9+616 1/4*7.9=7.9*1000=7900
0.125×2 3/4+1/8×6.25-12.5%=1/8*11/4+1/8*25/4-1/8=1/8*8=1

Answer 4

1/10=1/4-1/5 1/18=1/6-1/9 1/30=1/5-1/6 0.125=1/8