例：1个9是(9)，比(10)少(1)．

9个9相加是{#blank#}1{#/blank#}，比{#blank#}2{#/blank#}少{#blank#}3{#/blank#}．

8×4=       9×7 =         2×8=        7×8 – 8 =

8×9=       4×6=         9×8=        2×9+9=

8×2=       4×9=         8×7=        1 ×8 – 8 =

6×7=      6×6=       25-5=      36+9=

5×8=       21-4=       7×7=      7×8=

3×7=       7×9=       4×8=      36+42=

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

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