78
78/125
It is 78. There is no need for a decimal point after the number and it would be wrong to write it as 78.0 since that would suggest a level of accuracy that is not justified.
.78
4.8 written in word form is four and eight tenths.
0.624 = 624/1000 = 78/125
3 and 78 = 81.
x.xxx is a fraction. It is a fraction in decimal form rather than in the form of a ratio. However, that does not stop it being a fraction. And, since it is a decimal fraction, there is not another simpler decimal form. Its equivalent, in rational form, is 78/100 which can be simplified to 39/50.
.78
78% =0.7878/10039/50
78/100 as a decimal is 0.78
0.078