Giải bài tập 3 trang 65 vbt Toán 4 tập 2 Cánh diều

a)

$\frac{1}{2}\times \frac{1}{3}=\frac{1\times 1}{2\times 3}=\frac{1}{6}$

$\frac{1}{3}\times \frac{1}{2}=\frac{1\times 1}{3\times 2}=\frac{1}{6}$

Vậy $\frac{1}{2}\times \frac{1}{3}$ = $\frac{1}{3}\times \frac{1}{2}$

$\frac{3}{5}\times \frac{1}{6}=\frac{3\times 1}{5\times 6}=\frac{3}{30}=\frac{1}{10}$

$\frac{1}{6}\times \frac{3}{5}=\frac{1\times 3}{6\times 5}=\frac{3}{30}=\frac{1}{10}$

Vậy $\frac{3}{5}\times \frac{1}{6}$ = $\frac{1}{6}\times \frac{3}{5}$

b) Ví dụ:

$\frac{2}{9}\times \frac{1}{3}=\frac{2\times 1}{9\times 3}=\frac{2}{27}$

$\frac{1}{3}\times \frac{2}{9}=\frac{1\times 2}{3\times 9}=\frac{2}{27}$

Vậy $\frac{2}{9}\times \frac{1}{3}$ = $\frac{1}{3}\times \frac{2}{9}$