Can you help me understand how to do this please?

1/8
Explanation:The given expression is:
[tex]-\frac{1}{4}+\frac{3}{8}[/tex]Find the Least Common multiple(LCM) of the denominators
LCM of 4 and 8 = 8
After simplification, the addition expression then becomes:
[tex]\begin{gathered} \frac{-2(1)+1(3)}{8} \\ =\frac{-2+3}{8} \\ =\frac{1}{8} \end{gathered}[/tex]