想：4减8不够减，要把34分成20和14．先算14减8，得{#blank#}1{#/blank#}，再把20和{#blank#}2{#/blank#}合起来，得{#blank#}3{#/blank#}．

（从上到下，从左到右依次填写）

43 + 5 =         55 + 4 =         67 + 2 =       3 + 62 =

43 +50 =        55 +40 =         67 +20 =      30 +62 =

87 – 60 =        68 – 30 =        45 – 40 =      56 – 20 =

87 – 6 =         68 – 3 =         45 – 4 =        56 – 2 =

18{#blank#}1{#/blank#}3=15         81{#blank#}2{#/blank#}9=9         17{#blank#}3{#/blank#}5=22         2{#blank#}4{#/blank#}3=6