It sounds as though the formatting on the cell is possibly set to a whole number but formatting does not alter the underlying value (unless using Precision as Displayed which is not advised)

For ex... if we say cell A1 holds your value - what does =MOD(A1,1) return ?
I presume 0.2 ?

If you want A1 to hold 45 rather than 45.2 you need to alter the value - if it's generated by a formula, ie A1: =B1 and B1 holds 45.2 you can get A1 to hold 45 by using: =ROUND(B1,0)

Alternatively you can alter your other formulae where you are multiplying A1 by using ROUND at that point, eg:

C1 =ROUND(A1,0)*2

should equal 90 rather than 90.4

Does that help ?