①19.6-5.6×1.05
②4.05÷0.5+10.75
③10.5÷(8.4-4.9)
④4.8×0.27+5.2×0.27
⑤89.89÷1.25÷8
⑥(7.89+7.89+7.89+7.89)×0.25