4.5:20%= 25公顷:
36×()= ÷3= 25%+(-12.5%)÷=
口诀:
①4.7﹣0.7×1.5﹣0.75
② ÷[( + )× ]
③25×4.9×4
④35×25×( )
⑤5600÷(7×25)
⑥13×(10+0.2)