脱式计算 能简算的要简算4/11-6/13+7/9*(9/11-9/13) [1-(1/10+1/12+1/15)*2]

4/11-6/13+7/9*(9/11-9/13)
=4/11-6/13+7/9x9/11-7/9x9/13
=4/11-6/13+7/11-7/13
=(4/11+7/11)-(6/13+7/13).加法交换律和连减的简便计算
=1-1
=0
[1-(1/10+1/12+1/15)*2]/1/15
=[1-(1/10+1/12+1/15)*2]x15
=[1-(1/5+1/6+2/15)]x15
=1x15-1/5x15-1/6x15-2/15x15.乘法分配律
=15-3-5/2-2
=15/2

4/11-6/13+7/9*(9/11-9/13) =4/11-6/13+7/9×9/11-7/9×9/13 =4/11+7/11-（6/13+7/13） =1-1 =0
[1-(1/10+1/12+1/15)*2]/1/15 =【1-1/4×2】×15 =1/2×15 =7.5
所以 计算完4/11-6/13+7/9*(9/11-9/13) [1-(1/10+1/12+1/15)*2]/1/15

4/11-6/13+7/9*(9/11-9/13)
=4/11-6/13+7/9×9/11-7/9×9/13
=4/11+7/11-（6/13+7/13）
=1-1
=0
[1-(1/10+1/12+1/15)*2]/1/15
=【1-1/4×2】×15
=1/2×15
=7.5