△＋(○＋□)=(△＋○)＋□

0.34×1.1{#blank#}1{#/blank#}0.34        5.5{#blank#}2{#/blank#}5.5÷0.9

4.5×0.2{#blank#}3{#/blank#}4.5÷0.2      8.75÷2.5{#blank#}4{#/blank#}87.5÷0.25

8.6×1.02{#blank#}1{#/blank#}8.6          1.8÷0.1{#blank#}2{#/blank#}1.8×10

7.6÷0.85{#blank#}3{#/blank#}7.6          0.92×0.85{#blank#}4{#/blank#}0.85

4.09×1.2{#blank#}1{#/blank#}4.09          9.84÷2{#blank#}2{#/blank#}9.84

1.6×0.37{#blank#}3{#/blank#}1.6           3.7×100+3.7{#blank#}4{#/blank#}3.7×101

2.4÷0.6{#blank#}5{#/blank#}2.4            4.9÷2.8{#blank#}6{#/blank#}4.9÷0.7

①商不变的规律      ②乘法分配律         ③加法结合律        ④分数的基本性质