Đáp án:
$\begin{array}{l}
h)\sqrt 5 - 2,5\\
= \sqrt 5 - \dfrac{5}{2}\\
= \sqrt 5 - \sqrt {\dfrac{{25}}{4}} \\
Do:5 < \dfrac{{25}}{4}\\
\Leftrightarrow \sqrt 5 < \sqrt {\dfrac{{25}}{4}} \\
\Leftrightarrow \sqrt 5 - 2,5 < 0\\
i)2 + \sqrt 3 \\
3,5 = 2 + 1,5 = 2 + \dfrac{3}{2} = 2 + \sqrt {\dfrac{9}{4}} \\
Do:3 > \dfrac{9}{4}\\
\Leftrightarrow \sqrt 3 > \sqrt {\dfrac{9}{4}} \\
\Leftrightarrow 2 + \sqrt 3 > 2 + 1,5\\
\Leftrightarrow 2 + \sqrt 3 > 3,5\\
j)4 - \sqrt 2 \\
3 = 4 - 1 > 4 - \sqrt 2 \\
\Leftrightarrow 4 - \sqrt 2 < 3
\end{array}$
