20
Twenty
How old is he?
He is 45 years old
How old is her aunt?
Her aunt is twenty one years old
What number is it?
One hundred
What number is this?
Five thousand
What number in his shirt?
Ninety nine
What number can you see?
One million
What number is it?
One billion
How old is your grandfather?
My grandfather is 53 years old
How many letters can you count?
Thirteen
How many students are there?
There are thirty students
