5.31×1.8{#blank#}1{#/blank#}5.31       

3.9÷1.8{#blank#}2{#/blank#}3.9

7.6×1.2{#blank#}3{#/blank#}7.6÷1.2     

4.5÷0.5{#blank#}4{#/blank#}4.5×2．

3.7÷0.25={#blank#}1{#/blank#}÷2.5      0.3÷0.002={#blank#}2{#/blank#}÷2

× {#blank#}1{#/blank#}             ÷ {#blank#}2{#/blank#}

÷ {#blank#}3{#/blank#}             6× {#blank#}4{#/blank#}6÷

× {#blank#}5{#/blank#}            （48+12）× {#blank#}6{#/blank#}48+12×

1.6×0.13{#blank#}1{#/blank#}1.6       1.6×2.3{#blank#}2{#/blank#}2.3

{#blank#}3{#/blank#}       2.07÷3.1{#blank#}4{#/blank#}1

0.55÷0.89{#blank#}5{#/blank#}0.55    5.67÷0.12{#blank#}6{#/blank#}56.7÷1.2