For numbers between 10 and 40 Russians use дцать. What is дцать? A very Russian way to say десять? A word made of multiple parts, each of which do have a meaning, like дца and ть, as in еха-ть? (I would hope not!). I just cannot understand, where it comes from, as I cannot think of any words which have дцать, except for numbers in range from 10 to 40!
Thank you in advance!