One point Five ... OR One and a Half
Fifteen
It's written as.. fifteen
15 = fifteen
fifteen minus b
fifteen million
" fifteen minus 'bee' "
Fifteen degrees.
You already have in the question.
15
15 million, seven hundreds and sixty-three thousand, one hundred an forty-five
Write "9" then the forward slash "/" and then "15". Or you can write the 9 above a horizontal line with the 15 below that line.
You write it as 3/15. However, that can be simplified to 1/5.