9×0+1=1 9×123+4=
9×1+2=11 9×1234+5=
9×12+3=111 9×+=
48×21=48×20+{#blank#}3{#/blank#},11×50-11=11×{#blank#}4{#/blank#},25×4×6=25×{#blank#}5{#/blank#}。
②99×9=891=900-9
③999×9=8991={#blank#}1{#/blank#}-{#blank#}2{#/blank#}
④9999×9={#blank#}3{#/blank#}={#blank#}4{#/blank#}-{#blank#}5{#/blank#}