What is 7/25 in decimal form

Every fraction is just a short way to write a division.
Whenever you see a fraction, it means

            the top number
divided by
            the bottom number.

When you actually do the division, like with a pencil or a calculator,
the quotient you get is the decimal form of the fraction.

I won't insult your intelligence by giving you  7  divided by  25 .
I'm sure you can do that easily.

I also won't insult your intelligence by sending you to a web site.
I assume that if you were on a desert island without your phone
or any 4G coverage, you'd be able to figure out a way to divide
7 by 25.

The discount is 8.70 . you dont tell us the percent of tax added so there is no way to find out, unless i'm not seeing anything. without tax its 37.70

Were is the problem