①421×13=
②45×380=
③504×26=
④399÷57=
⑤*820÷50=
10﹣6.8= ﹣ = 35×1%= 1.25×24= 5× ÷5× =
0.42= 10÷0.02= 5a×7a= 1÷3= 1﹣1÷6=