3.9×0.96{#blank#}1{#/blank#}3.9

0.63÷0.63{#blank#}2{#/blank#}0.63

5.6×1.02{#blank#}3{#/blank#}5.6

1.26÷0.98{#blank#}4{#/blank#}1.26×0.98．

3.5×0.99{#blank#}1{#/blank#}3.5

23.2×0.9{#blank#}2{#/blank#}0.9

2.76×1.52{#blank#}3{#/blank#}1.52

4.25×1.1{#blank#}4{#/blank#}4.25

1×0.44{#blank#}5{#/blank#}0.44

7.1×0.54{#blank#}6{#/blank#}7.1×5.4

198×0.8{#blank#}1{#/blank#}198      95×0.9{#blank#}2{#/blank#}95

168×1.5{#blank#}3{#/blank#}168      132×4.6{#blank#}4{#/blank#}132

42×5={#blank#}1{#/blank#}

42×20={#blank#}2{#/blank#}

21×5={#blank#}3{#/blank#}

21×20={#blank#}4{#/blank#}

（42×2）×（10÷{#blank#}5{#/blank#}）=420

（42×{#blank#}6{#/blank#}）×（10÷10）=420