①48-9=
②35+21=
③72+27=
④72-35=
⑤17+28+23=
⑥61-9-13=
15-7= 8+5= 7+6= 18-9=
19-5= 12-9= 16-8= 11-2-1=
8+8= 9+5= 13-5= 12-3+3=
①79-53=
②34+37=
③91-42=
④58+22-43=
①53+27=
②90-65=
③77-7=
④6+78=
⑤85-38=
⑥51-15=
18×30=
24×30=
140÷4=
280÷4=