4.86×99={#blank#}1{#/blank#}

3.1×4×0.25=3.1×(4×0.25)运用了乘法交换律

40－6.23－3.77=40－({#blank#}1{#/blank#}   {#blank#}2{#/blank#}   {#blank#}3{#/blank#})

51×102                            0.8××12.5          ×7÷×7

83.47﹣（23.47+11）      45×99+45             1÷2.5+2.5×0.8

2.5×(4+0.4)               14.8×0.25+6.3

9.52÷3.4+7.2          3.69÷(3.69÷0.3)

（3.5+2.5）×{#blank#}1{#/blank#}=3.5×{#blank#}2{#/blank#}+{#blank#}3{#/blank#}×4

4.87×99=4.87×（{#blank#}4{#/blank#}-{#blank#}5{#/blank#}）