青蛙过河．

{#blank#}1{#/blank#}×5＜42

8×{#blank#}2{#/blank#}＜57

{#blank#}3{#/blank#}×3＜25

8×{#blank#}4{#/blank#}＜50

1×8={#blank#}1{#/blank#}×4

1×8={#blank#}2{#/blank#}×2

3×7{#blank#}1{#/blank#}20         5×6{#blank#}2{#/blank#}3×9         6+6{#blank#}3{#/blank#}5×5

4×5{#blank#}4{#/blank#}18         7×2{#blank#}5{#/blank#}8×2         30+5{#blank#}6{#/blank#}7×5

5角{#blank#}7{#/blank#}50分      36角{#blank#}8{#/blank#}6元3角     40元{#blank#}9{#/blank#}26元+4元