# Mac Numbers formula question

Discussion in 'Mac Apps and Mac App Store' started by manxkipper, May 27, 2009.

1. ### manxkipper macrumors newbie

Joined:
May 27, 2009
#1
I want to set up a cell that has a number in it. That number is to decrease by one every seven days is there a formula that I can use to do this automatically

2. ### DSG macrumors regular

Joined:
Jul 11, 2008
#2
I don't use Numbers but in Excel, a suitable formula would be:

=[Initial]-INT((TODAY()-DATE([Year], [Month], [Day]))/7)

Where [Initial] is the starting value and [Year], [Month] and [Day] refer to the day on which you want the countdown to start. Hence, a cell that started at 100 and reduced by 1 every 7 days from today would be generated by:

=100-INT((TODAY()-DATE(2009, 5, 27))/7)

I assume Numbers has equivalent functions. INT() is the integer function - it returns the portion of the expression in the brackets that is a whole number and disregards the rest (i.e. the decimal value) - otherwise the initial number would decrease by 1/7 each day. TODAY() returns today's date and DATE() returns the date defined by the terms in the brackets.

Hope that helps!

3. ### manxkipper thread starter macrumors newbie

Joined:
May 27, 2009
#3
Yes it did thanks. Numbers did not let me do the INT of Today but by splitting the formula into two cells it worked. A bit messy but hey it works

4. ### Pmatth macrumors newbie

Joined:
Dec 26, 2011
#4
Sample

Hi Manxkipper

I'm trying to do the same thing in numbers could you post a copy/sample of your formula?

Thanks
Paul