①23+47-39=
②85-18-29=
③45+17+35=
④90-36+15=
2×7= 6×3= 4×9= 9×2=
7×8= 9×7= 6×6= 6×8=
6×3+6= 7×5+7= 4×9+9=
7×8-8= 1×9-9= 8×7-7=