(にじゅう)

にじゅう
number
twenty
1. twenty
The number twenty. Formed by combining () (two) and (じゅう) (ten), literally meaning 'two tens.'
二十(にじゅう)(えん)です
It's twenty yen.
It takes about twenty minutes.
This book has twenty pages.
In Japan, you can drink alcohol from twenty years old.
I turned twenty this year. Since I'm an adult now, I want to make my own decisions.
Special reading はたち for age 20

Twenty has a special reading 二十(はたち) specifically when referring to age (turning 20). This is because 20 is traditionally the age of adulthood in Japan. In other contexts, 二十(にじゅう) is used. The Japanese number system is very regular: tens are formed by [number] + (じゅう).