casting types

[Stribor40 <ikamzic@gmail.com>]

I have problem understanding this explicit conversion of types....

 var1: FLOAT;
 
 tmp := Float(x) / 20.0 + Float(y)/ 30.0 + Float(z)/40.0;
 return var1 - truncated type of var1

Example if var1 = 123.456 then
  return  123.456 - 123 

which is 0.123

How would I cast var1 to become 123 but still be able to subtract it from var1 and keep float type?