The Shilling unit based on older British monetary unit where 20 shilling=1 Pound (£). That is why we still call 20 shillings in matatu language mbao, mbao..(pound, pound). We dropped farthing and pence and took on cents to make money matters easy. you can imagine the math for 2 farthings (ndururu)=1 shilling, 12 pennies (Penny)=1 shilling and therefore, 100 cents (Hela moja) =1 shilling made sense (cents). That is why our 10 cents was/is erroneously called Penny Moja...close enough for an African discovering money. Actually, Hela moja=1 cent