I find your working way too complicated, but that's probably just teaching difference, I only used one formula n(moles) = c(Concentration) x V(Volume). You don't need to work out the molarity and the number of grams, cause you don't need to. n(sulfuric acid) = cV = 0.025(volume in litres) x 0.125 (conc.) = 0.003125 moles. So n(NaOH) = 0.00625 moles, therefore V(NaOH) = n/C = 0.00625/0.25 = 0.025 L = 25 mL = 25cm3. Really, this way is much faster and easier.