Heating Oil Calculator

I created a heating oil calculator. This little program tells you how much oil exist in your tank.
It also will tell you the total price once you enter the price per gallon. I find it to be a cool program.
The program is completed but not deployed or packaged. I have a textbox where a user can
enter the meter reading, which is in fractions. My program can only be used in decimal equivalent.
I would like to change that into using a fraction instead.
Here is the code :
The PreNumGal is where the user will enter the meter reading. I can only use the decimal equivalent in order to work.
I need to use a fraction rather than using the decimal. (e.g Not use 0.25, use 1/4) Can anyone help me.


PrivateSub btnCalculate_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnCalculate.Click

Dim NumGal, PriceGal, ExistNumGal, NumGalNeeded, TotPriceGal AsInteger

Dim PreNumGal AsShort

txtExistNumGal.Text = txtNumGal.Text * txtPreNumGal.Text

txtNumGalNeeded.Text = txtExistNumGal.Text - txtNumGal.Text

txtTotPriceGal.Text = txtNumGalNeeded.Text * txtPriceGal.Text

txtTotPriceGal.Text = Format(txtTotPriceGal.Text, "Currency")

txtPriceGal.Text = Format(txtPriceGal.Text, "Currency")

EndSub