Formula - How to hide a formula...

I know after i ll explain how to hide a formula, no formula will be hidden from who so ever reads it...
but still, here the trick goes...

Write the formula as usual.
Right Click on the cell/s and Select "Format Cells..." (or press Ctrl+1)
Select "Custom" (under "Category:") at left pane
Under "Type:" at right side, Type one Space
Press Enter

Woop, its done

BUTTT

If some one searches anything by formula under search options, then SORRY, no escape...