5.1÷17={#blank#}1{#/blank#}

0.26×0.4={#blank#}2{#/blank#}

0.27÷0.3={#blank#}3{#/blank#}

0.25×4={#blank#}4{#/blank#}

例：96×0.25

=24×4×0.25

=24×1

=24

0.125×64={#blank#}1{#/blank#}

1.8-0.8=     480÷4=     250×40=     49×30≈

0.3+0.7=    123÷3=     4500÷5=     723÷9≈

5.6+4.4=    5×7+5=     6×6+9=     21×78≈

1.7+2.05=    0.06×7=    0.9×0.8=    2.5×20=

1-0.92=    53.8÷10=    3.5×100=    0.93-0.5=

12.08×{#blank#}1{#/blank#}＜120              5.11×{#blank#}2{#/blank#}＜50

0.44×{#blank#}3{#/blank#}＜4                 16.81×{#blank#}4{#/blank#}＜33.62