9.60{#blank#}1{#/blank#}8.91      8.5+4.25{#blank#}2{#/blank#}12.75     86+47{#blank#}3{#/blank#}47+86

11.4{#blank#}4{#/blank#}15.11     10-4.3{#blank#}5{#/blank#}6.7        102×66{#blank#}6{#/blank#}100×66+2

乘法交换律：{#blank#}1{#/blank#}；

乘法结合律：{#blank#}2{#/blank#}；

乘法分配律：{#blank#}3{#/blank#}．

25×199＝25×{#blank#}1{#/blank#}；

（136+569）+431＝{#blank#}2{#/blank#}+（{#blank#}3{#/blank#}+{#blank#}4{#/blank#}）．

182+(606-286)÷5             [175-(89-21)]×23             125×(137+137×7)

6666×4444+3333×1112              100-99+99-98+…-+3-2+2-1