im confused

$$\\\frac{-7}{12}+\frac{3}{8}\\\\ =\frac{-7*8}{12*8}+\frac{3*12}{8*12}\\\\ =\frac{-56}{96}+\frac{36}{96}\\\\ =\frac{-56+36}{96}\\\\ =\frac{-(56-36)}{96}\\\\ =\frac{-(20)}{96}\\\\ =\frac{-(20\div 4)}{96\div 4}\\\\ =\frac{-5}{24}\\\\$$