Đúng ghi Đ, sai ghi S. a) 6/11 + 6/22 = 6/33

Đúng ghi Đ, sai ghi S.

a) \[\frac{6}{{11}} + \frac{6}{{22}} = \frac{6}{{33}}\]     S                 

b) \[\frac{2}{5} + \frac{7}{{10}} = \frac{{11}}{{10}}\]    Đ

c) \[\frac{6}{{13}} + \frac{7}{{26}} = \frac{9}{{26}}\]  S                 

d) \[\frac{3}{8} + \frac{1}{4} = \frac{5}{8}\]     Đ

Giải thích.

a) \[\frac{6}{{11}} + \frac{6}{{22}} = \frac{{12}}{{22}} + \frac{6}{{22}} = \frac{{18}}{{22}}\]                   

b) \[\frac{2}{5} + \frac{7}{{10}} = \frac{4}{{10}} + \frac{7}{{10}} = \frac{{11}}{{10}}\]                   

c) \[\frac{6}{{13}} + \frac{7}{{26}} = \frac{{12}}{{26}} + \frac{7}{{26}} = \frac{{19}}{{26}}\]                   

d) \[\frac{3}{8} + \frac{1}{4} = \frac{3}{8} + \frac{2}{8} = \frac{5}{8}\]