六年级数学四则运算题大全精编

六年级数学四则运算题大全28-(3.4+1.25×2.4)2.55×7.1+2.45×7.1777×9+1111×30.8×〔15.5-(3.21+5.79)〕（31.8+3.2×4）÷531.5×4