用10cm的直尺去量，需要量{#blank#}1{#/blank#}次

80={#blank#}2{#/blank#}×10

用小圆片摆一摆、分一分．

2×3 =           4×6 =          5×4 =          4 ×2 =

4×3=           3×5=           5×3=           5×6=

5×2=           4×5=           3×6=           5×5=

4×9=           2×8=           4×7=           8×3=

8×5=           7×3=           9×3=           9×5=

45÷5=       35÷7=        25-5=         70-52=

8×8=        400-300=     900+400=     2000+4000=

81÷9=       9×4=         36÷6=        54÷6=

4×{#blank#}1{#/blank#}<30       {#blank#}2{#/blank#}×8<40

9×{#blank#}3{#/blank#}<46       {#blank#}4{#/blank#}×5<37