To solve these subtraction problems, we need to remember that subtracting a negative number is equivalent to adding its positive counterpart. Therefore, for each expression, we will convert the subtraction of a negative number into an addition and then perform the arithmetic operation.
Step 1: Evaluate the First Expression
We start with the expression \( -4 - (-8) \). By converting the subtraction of a negative number into addition, we have:
\[
-4 - (-8) = -4 + 8
\]
Calculating this gives:
\[
-4 + 8 = 4
\]
Step 2: Evaluate the Second Expression
Next, we evaluate the expression \( 7 - (-7) \). Again, we convert the subtraction of a negative number into addition:
\[
7 - (-7) = 7 + 7
\]
Calculating this gives:
\[
7 + 7 = 14
\]
Final Answer
The results of the calculations are:
\[
\boxed{4}
\]
and
\[
\boxed{14}
\]