Fifty is the number equal to five times ten. It comes after forty-nine and before fifty-one.
It comes from Old English “fīftig,” made from “fīf” (five) and “tig” (a group of ten). Similar patterns appear in other Germanic languages.
The “-ty” in “fifty” quietly means “times ten,” just like “-teen” means “plus ten.” Once you notice this, English number words turn into mini math lessons about multiplication and addition.
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