①2.87×(63-2.3)
②54.7-45.3÷15
③2.008×1999+2.008
④10.8÷[(5.28-1.68)×0.3]
⑤3.69÷(1.23×0.5)
⑥(5.28+5.28+5.28+5.28)×0.25