Giải câu 1 trang 167 toán tiếng anh lớp 4.
$\frac{2}{7} + \frac{4}{7}= \frac{6}{7}$
$\frac{6}{7} - \frac{2}{7}= \frac{5}{7}$
$\frac{6}{7} - \frac{4}{7}= \frac{2}{7}$
$\frac{4}{7} + \frac{2}{7}= \frac{6}{7}$
$\frac{1}{3} + \frac{5}{12}= \frac{4}{12}+ \frac{5}{12}=\frac{9}{12}$
$\frac{9}{12} - \frac{1}{3}= \frac{9}{12} - \frac{4}{12}=\frac{5}{12}$
$\frac{9}{12} - \frac{5}{12}= \frac{4}{12}$
$\frac{5}{12} + \frac{1}{3}= \frac{5}{12}+ \frac{4}{12}=\frac{9}{12}$