1. 师傅和徒弟两人共做了36只风筝，其中师傅做的风筝只数是徒弟的3倍，师傅和徒弟各做了多少只风筝？(列方程解答)

解:设徒弟做了$x$只风筝。
$x + 3x = 36$
$x = 9$
师傅:$3 × 9 = 27$(只)

2. 水果店运来一批水果共重 320 kg,下午卖出这批水果的$\frac{1}{2}$,下午卖出多少千克水果?

$320 × \frac{1}{2} = 160(\mathrm{kg})$

算一算
$20 ÷ \frac{1}{2} =$
$5 ÷ \frac{5}{21} =$
$6 ÷ \frac{5}{6} =$
$12 ÷ \frac{1}{4} =$
$2 ÷ \frac{3}{8} =$
$4 ÷ \frac{3}{4} =$
$10 ÷ \frac{2}{5} =$
$10 ÷ \frac{4}{5} =$
$45 ÷ \frac{3}{5} =$
$15 ÷ \frac{15}{16} =$

20 ÷ $\frac{1}{2}$ = 20 × 2 = 40
5 ÷ $\frac{5}{21}$ = 5 × $\frac{21}{5}$ = 21
6 ÷ $\frac{5}{6}$ = 6 × $\frac{6}{5}$ = $\frac{36}{5}$
12 ÷ $\frac{1}{4}$ = 12 × 4 = 48
2 ÷ $\frac{3}{8}$ = 2 × $\frac{8}{3}$ = $\frac{16}{3}$
4 ÷ $\frac{3}{4}$ = 4 × $\frac{4}{3}$ = $\frac{16}{3}$
10 ÷ $\frac{2}{5}$ = 10 × $\frac{5}{2}$ = 25
10 ÷ $\frac{4}{5}$ = 10 × $\frac{5}{4}$ = $\frac{25}{2}$
45 ÷ $\frac{3}{5}$ = 45 × $\frac{5}{3}$ = 75
15 ÷ $\frac{15}{16}$ = 15 × $\frac{16}{15}$ = 16