Expression palette: Click on $\sqrt{a}$. Type 2 in the field "$a$".
Exit the radical with the right-arrow key.

Context Panel: Approximate≻10 (digits)

Use the vertical stroke character for the absolute-value bars, or click on $\left|a\right|$ in the Expression palette.

Context Panel: Evaluate and Display Inline

Enter the exponential e.

To raise the cursor for the exponent, type ^ (i.e.,Shift+6).

Context Panel: Approximate≻10 (digits)

Type either $\ln \left(4\right)$ or $\log \left(4\right)$ to obtain the natural logarithm.

Context Panel: Approximate≻10 (digits)

Type ${\log }_2\left(8\right)$.

Context Panel: Evaluate and Display Inline

Use the sqrt and evalf commands.

$$\begin{gathered} q≔\frac{\mathrm{sqrt}\left(2\right)}{3}\; \\ \mathrm{evalf}\left(q\right) \end{gathered}$$

Use the abs command.

$\mathrm{abs}\left(-5\right)$

Enter the exponential function with the exp command.

$$\begin{gathered} q≔\exp \left(-3\right)\; \\ \mathrm{evalf}\left(-3\right) \end{gathered}$$

Enter the natural logarithm with the ln (or log) command.

$$\begin{gathered} q≔\ln \left(4\right)\; \\ \mathrm{evalf}\left(q\right) \end{gathered}$$

Enter ${\log }_2$ with square brackets, as shown to the right.

$\log \left[2\right]\left(8\right)$