①100-2.28×1.5
②5.4+4.6×0.5
③12.5×8.8
④50+2.8×38-28.5÷15
73.5÷12.5÷8
12-11.5÷2.5
3.6÷1.2- 0.8×2.7
(6.5×2.8-5.6)÷1.2