11－4＝ → －5＝ → ＋ ＝

{#blank#}1{#/blank#}＋5=9          1＋{#blank#}2{#/blank#}=7           4 ＋{#blank#}3{#/blank#}=8

3＋{#blank#}4{#/blank#}=8         {#blank#}5{#/blank#}＋4=6            {#blank#}6{#/blank#}＋4=7

4－3{#blank#}1{#/blank#}4     5＋0{#blank#}2{#/blank#}5－0     2＋7{#blank#}3{#/blank#}5＋3      9－4{#blank#}4{#/blank#}8－5

5{#blank#}1{#/blank#}5              9{#blank#}2{#/blank#}8

7{#blank#}3{#/blank#}3+5         4+3{#blank#}4{#/blank#}8-1