 Though the Romans used a decimal system for whole numbers, reflecting how they counted in Latin, they used a duodecimal system for fractions, because the divisibility of twelve makes it easier to handle the common fractions of and than does a system based on ten On coins, many of which had values that were duodecimal fractions of the unit , they used a tally-like notational system based on twelfths and halves.A dot (·) indicated an "twelfth", the source of the English words "inch" and "ounce"; dots were repeated for fractions up to five twelfths.Six twelfths (one half) was abbreviated as the letter "S" for "half".