w/o using SUMPRODUCT and using formula for sum of arithmetic
progression you might use the following:

A1=100000
A2=1500
A3=15
A4=12 (or number of months generally)

=A4*(2*(A1-A2)-(A4-1)*A3)/2

HIH


On 7 Maj, 07:56, JV wrote:
Hello,

Is there a formula which could answer the following?

Monthly deduction is $1,500 in January of 2009 and drops by $15 per month.. *
What are the totals for 2009, 2010 and 2011?

Thanks in advance for the help.