I am trying to add a series of numbers using a Date Range formula, however, I
am trying to add a criteria that would look at another column as well. For
example, assume the following:

Date Probability Amount
01/08 90% $1,000,000
01/08 100% $2,000,000
02/08 75% $1,250,000
02/08 100% $2,500,000

I want to sum by month and probability. I have the following date formula

=SUMPRODUCT((MONTH($N$2:$N$30)=MONTH($B$33))*(YEAR ($N$2:$N$30)=YEAR($B$33))*(C2:C30))

How do I add a qualifier to this formula to have it look at the probability
as well - for instance add all values where the probability is less than
100%,

I appreciate your assistance.