The "data of each variable" and the variable itself are one and the same thing. Just assign it to another variable if you want, or just start using it.
someOtherVariable = day1;
someOtherVariable2 = day2 * pi * log(42);
someOtherVariable3 = day5 * cos(day12) + day9;
result = SomeFunction(day7);
and so on. You don't need to do anything special to the variable to access it's "data". The variable and its data are the very same thing.