脱式计算,怎样简便就怎样算。①63.35-4.75+5.25 ②3.89+2.67+0.15 ③8.1+6.93+1.9+0.07 ④46.5-(13.55+7.2) ⑤20-12.64-3.36 ⑥39.74-(9.74+8.69)

脱式计算,怎样简便就怎样算。①63.35-4.75+5.25 ②3.89+2.67+0.15 ③8.1+6.93+1.9+0.07 ④46.5-(13.55+7.2) ⑤20-12.64-3.36 ⑥39.74-(9.74+8.69)

[答案]解:①63.35-4.75+5.25 =58.6+5.25 =63.85 ②3.89+2.67+0.15 =6.56+0.15 =6.71 ③8.1+6.93+1.9+0.07 =(8.1+1.9)+(6.93+0.07) =10+7 =17 ④46.5-(13.55+7.2) =46.5-20.75 =25.75 ⑤20-12.64-3.36 =20-(12.64+3.36) =20-16 =4 ⑥39.74-(9.74+8.69) =39.74-9.74-8.69 =30-8.69 =21.31