Increments of 0.5

Hi,
Basically i want a cell to raise by increments of 0.5 depending on the value of another cell
I 've tried figure out a calculation to do this but to no avail unless i'm missing something simple

If there are 4 hours in a half day, i need to divide the hours cell by that number to get the number of
half days then get a second cell to display that in increment of 0.5 so: -
4 hours would = 0.5
8 hours would = 1.0
16 hours would = 2

but heres the tricky bit

anything between the divisables of 0.5 should be roundedup to the nearest 0.5 so:
5 hours would = 1.0
6 hours would = 1.0
9 hours would = 1.5
17 hours would = 2.5
etc

any ideas?

Thanks

Can you please explain the problem once again... I couldn't get what were you sayin.. do u took the variables as variant or integer?? plz eleborate your prob..

That brilliant thanks,

i figure it out using the MOD() function then adding the different but that alot cleaner

Thanks,