Câu 4: Trang 59 sách VNEN toán 4
Tính:
$\frac{3}{5}\times \frac{5}{3}$
$\frac{5}{9}\times \frac{9}{5}$
$\frac{1}{3}\times \frac{3}{1}$
Bài Làm:
$\frac{3}{5}\times \frac{5}{3}=\frac{15}{15}$
$\frac{5}{9}\times \frac{9}{5}=\frac{45}{45}$
$\frac{1}{3}\times \frac{3}{1}=\frac{3}{3}$