... I divide this by 2 I get a fractional value of 0.5 in decimal I need to know how can I use this value or how I could represent this value in the controller for manipulation of further tasks.

You can not work with fractionals, only display them.

Say you want two digits after the decimal point on your display, you just represent all values internal to the '51 as (value*100), then when you display, you just insert a decimal point at the right place.

Erik