12,8 dibagi 1 per 25 ditambah 61 per 4

12,8 = 128/100
128/100 : 1/25 = 128/100 * 25 = 128/4 = 32
32 + 61/4 = 128/4 + 61/4 = 189/4 = 47,25

1,28 : 1/25 + 61/4
= 1.28 * 25/1 + 61/4
= 702.5 + 15.25
= 717.75

maaf kalau salah