ثُمَّ فِي كُلِّ أَرْبَعَةِ مَثَاقِيلَ: قِيرَاطَانِ.
Translation: Then two qirats are due for every four mithqals.
A qirat is a smaller weight unit of gold. The rule expresses the additional due as two qirats per four mithqals.
Two qirats per four mithqals also amount to 2.5 percent. The difference among jurists concerns whether that increment must be complete.