阿里有 5 l 苹果汁。他把所有的果汁倒进杯子里。每个杯子的容量是 $\frac{7}{10}$ l。他装完所有果汁最少需要多少个杯子？ 答案：___

1. Divide the total volume of juice by the capacity of one cup

$5 \div \frac{7}{10} = 5 \times \frac{10}{7} = \frac{50}{7} = 7\frac{1}{7}$

2. Interpret the result to find the least number of cups needed

Since $7$ cups can only hold $7 \times \frac{7}{10} = 4.9$ litres, an additional cup is needed for the remaining juice. Therefore, $8$ cups are needed.