data validation formula for 1st date of a month

[faizee]

I need the formula to put in validation, that user could only enter 1st date of any month.
like 1/jan/12 or 1/dec/13

 

[Gary's Student]

For say cell A1, use Data Validation > Custom > Formula:

=DAY(A1)=1

 

[pjmorris]

Select the cells you need the validation in by clicking and dragging from top left to bottom right.
Then select Data Validation, choose Custom, enter the following equation =DAY(A1)=1 change the A1 to whichever is the top left cell in the selection.

Regards

 

[faizee]

thanks guys!
its pretty simple, i couldnt get that idea....