4×{#blank#}1{#/blank#}<21                  {#blank#}2{#/blank#}×5<38               28>{#blank#}3{#/blank#}×4

45÷5>{#blank#}4{#/blank#}×4               3×{#blank#}5{#/blank#}<25              3×{#blank#}6{#/blank#}<20

4×{#blank#}1{#/blank#}<29       45>{#blank#}2{#/blank#}×8

{#blank#}3{#/blank#}×9 < 40          55>6×{#blank#}4{#/blank#}

①5×8-3=37(个)                           
②5×7+2=37(个)                           
③2×8=16(个)   3×7=21(个)   16+21=37(个)