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manxkipper

macrumors newbie
Original poster
May 27, 2009
2
0
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
 
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!
 
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!

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

Thank you for your help
 
Sample

Hi Manxkipper

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

Thanks
Paul
 
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