简便计算13-2.9-2.09.2.009===1.234*.456.7+0.1234*12345+0.01234*53
1个回答
1.=13-(3-0.1)-(2+0.1-0.01)-(2+0.01-0.001)
=12-3+0.1-2-0.1+0.01-2-0.01+0.001
=13-3-2-2+0.001
=6.001
2.=0.1234*4567+0.1234*12345+0.1234*53088
=0.1234*(4567+12345+53088)
=0.1234*70000
=8638
3.=41.2*9*0.9+53.7*(1+0.9)+11*(1+0.25)
=370.8*0.9+53.7*0.9+53.7+11+2.75
=0.9*424.5+67.45
=382.05+67.45
=449.5
（1+0.12+0.23）*(0.12+0.23+0.34）-（1+0.12+0.23+0.34）*（0.12+0.23）
设A=0.12+0.23 B=0.12+0.23+0.34
原式=（1+A)B-(1+B)A
=B+AB-AB-A
=B-A
=0.12+0.23+0.34-0.12-0.23
=0.34
