=800-800
=0
=2.1÷2.1
=1
①(2.3+2.3+2.3+2.3)×2.5
②7.2×85%+2.8×0.85
③( + - )×24
④ ÷[ ×( - )]
⑤[( -0.25)× +0.3]÷
①1.25×(30.1﹣24.91÷4.7)
②[ ﹣( ﹣ )]÷
③15.6×13.1﹣15.6﹣15.6×2.1
④2 ×23.4+11.1×57.6+6.54×28
⑤1234+2341+3412+4123
⑥ + + + + +