How to do a subtraction from previous cell

[khandu]

Hey Guys

So I have to do something like this

Whatever value I put in Col A has to be subtracted from the value 1 cell previous to col A

So A2-A1 = result
then A3-A2 = result
A4-A3 = result

this has to go on in Column B as long as I keep putting value in col A. So I think I have to put some formula in Col B and drag it all the way down ..

please help :D

 

[Makrini]

you mean like...

in b2

=a2-a1

and drag down?