①1-+
②+++
③-(+)
④+-
①+2-1÷7 ②-(-)
③-+-2.75 ④+++++
①
⑵
③
④
②
①÷×
②×3.2+6.8÷
③105×(+)
④﹣+﹣
⑤6.4÷[(3﹣1.4)×]
①15 -4.25-5
②19.82-6.57-3.43
③4.6+3 +6 +5.4
④4 +2.25+5 +7
⑤9.63÷2.5÷4
⑥8.37-3.25-(1.37+1.75)