Three and eight times a number.
Three hundred eight.
If you mean three and eight tenths then it is 3 and 8/10 as a mixed number
You would write it like this: 308,000,000,000
3n
Seven point four three eight.
3.8
Well, honey, you write the number 23.8 as "twenty-three point eight." It's as simple as that. Just say it like you mean it and move on with your fabulous self.
7
125
three tenths is 3/10 eight tenths is 8/10
Twelve and eight hundred seventy-three thousandths.