Đề bài

Chọn dấu “<”, “>”, “=” thích hợp cho :

a) $\dfrac{5}{6} - {\left( {\dfrac{1}{6}} \right)^2}$ ... ${\left( {\dfrac{5}{6} - \dfrac{1}{6}} \right)^2}$;

b) $250.{\left( {\dfrac{1}{5} - \dfrac{1}{6}} \right)^2}$ ... $250.{\left( {\dfrac{1}{5}} \right)^2} - \dfrac{1}{6}$;

c) $3\dfrac{1}{5}:1,5 + 4\dfrac{2}{5}:1,5$ ... $\left( {3\dfrac{1}{5} + 4\dfrac{2}{5}} \right):1,5$;

d) $\left( {\dfrac{9}{{25}} - 2,18} \right):\left( {3\dfrac{4}{5} + 0,2} \right)$ ... $\dfrac{9}{{25}}:3\dfrac{4}{5} - 2,18:0,2$.