Question

几道简算题5

计算下面各题：
1．54又2/5÷17
2．238÷238又238/239
3．163又1/13÷41又1/39

Answer 1

1．54又2/5÷17
= （51＋3又2/5）÷17
= 51＋17/5÷17
= 3又1/5

2．238÷238又238/239
= 238÷（238×239＋238）/239
= 238÷【238×（239＋1）】/239
= 238×239/（238×240）
= 239/240

3．163又1/13÷41又1/39
= （123又1/13＋40）÷41又1/39
= 3＋40÷41又1/39
= 3＋40÷（41×39＋1）/39
= 3＋40÷（40×39＋39＋1）/39
= 3＋40÷【40×（39＋1）】/39
= 3＋40×39/（40×40）
= 3又39/40

Answer 2

1. 54.4/17=3.2
2. 238/(238+238/239)=1/(1+1/239)=239/240
3. (163+1/13)/(41+1/39)=3.975