小立有17本书,送给同学10本,又买来5本,现在有12本.
①64+27=
②75-67=
③38+12+29=
④90-45-27=
⑤91-47+28=
⑥80-(36+25)=
①72-38=
②69+27=
③43-8=
④56-12-17=
⑤46+25+13=
⑥43-(27-15)=