Add without using number line.

$\left(-8\right)+\left(+8\right)$

Add without using number line.

$-215+\left(+100\right)$

Add without using number line.

$\left(-110\right)+\left(-22\right)$

Add without using number line.

$17+\left(-11\right)$

Simplify:

$\left(-6\right)+\left(-10\right)+5+17$