"12" in Engpsh can be written as "twelve" or as the number "12".
The origin of the word "twelve" comes from the Old Engpsh word "twelf", which is related to the Germanic word "zwölf".
Examples:
The baker has twelve loaves of bread in the oven.
(面包师傅在烤箱里有12个面包)
My sister is twelve years old.
(我的妹妹12岁了)