How to make a value invisible

[Meenie]

I have Excel 2003 and Windows Vista Home Premium.
I'm definitely not an excel pro! but I do know how to make basic formulas.
I'm creating a sheet so people in a weight loss group can enter their weight and inches, then each week can enter their new weight and inches and see, at a glance, how much they've lost that week.
I can set that up without a problem.
but on the future weeks, in the loss column, the original weight and inches show up - I'd like them to be invisible until the new loss amount for that week is entered, then see the amount of loss and I can't figure out how to do that. Is there a simple way to do this? or am I stuck with seeing the original numbers until the new loss is entered?
I tried to snip a screen shot to put here, but it doesn't work.

 

[AlphaFrog]

Wrap your weight-loss formula in an IF function.

The example below will return blank until there is a value entered in B1 (your current week weight)

=IF(B1="","", A1-B1)

A1- B1 is the weight-loss formula.

 

[Meenie]

THANK you, AlphaFrog! That's IT. I knew I had done this years ago, but couldn't for the life of me remember how.
Thank you so very much. I really do appreciate it

Wrap your weight-loss formula in an IF function.

The example below will return blank until there is a value entered in B1 (your current week weight)

=IF(B1="","", A1-B1)

A1- B1 is the weight-loss formula.

 

[AlphaFrog]

You're welcome. Thanks for the feedback. I see you're adept at BB formatting.