1) fifteen, seventeen.
fifty, ninety.
2) nineteen, ninety
"fifty", "sixty"
3) 817 - eight one SEVEN
1989 - nineteen eighty NINE
How much does it cost? - It's $17.99
What time is it? - It's five fifteen.
How old are they? - He's forty FIVE, and his wife is thirty NINE.
— — — — — — — — — — — — — — —
fifth, sixth, seventh
19 th - nineteenth
20 th twentieth
30 th thirtieth