#### Answer

$-5.5$

#### Work Step by Step

The addends have different signs, so to add them, perform the following steps:
(1) Subtract the smaller absolute value from the bigger absolute value.
$|-7.9|-|2.4| = 7.9-2.4 =5.5$
(2) The sum will have the same sign as the number with the bigger absolute value.
$|-7.9|\gt |2.4|$
Thus,
$-7.9+2.4=-5.5$