选数填空。
10 20
30 40 50
60 70 80
{#blank#}1{#/blank#}×{#blank#}2{#/blank#}=500 {#blank#}3{#/blank#}×{#blank#}4{#/blank#}=1200
{#blank#}5{#/blank#}×{#blank#}6{#/blank#}=3200 {#blank#}7{#/blank#}×{#blank#}8{#/blank#}=3000
{#blank#}9{#/blank#}×{#blank#}10{#/blank#}=2100 {#blank#}11{#/blank#}×{#blank#}12{#/blank#}=5600
