28－7=       5×8 =        28－16 =         6×4 =          50－6 =

45+7 =        22+60=        6×7 =        7×8－8=         5×5+6=

35+20+6=     62+29=       91-23=       28+45+5=      53-（37+9）=       

36+18=       7×9+15=     6×5+29=     5×9-9=       9×6－16= 

2×5{#blank#}1{#/blank#} 7           6+6{#blank#}2{#/blank#} 36       5+4+3{#blank#}3{#/blank#} 3×4

3+3{#blank#}4{#/blank#}3×3       2×2{#blank#}5{#/blank#} 1×4     5×4-4{#blank#}6{#/blank#} 4×5-5