sum formula with overlaping references

[RBall]

B C D E F G H I J
K L M N

LAST

SIX
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV
DEC MON
1.2 1.0 2.3 1.6 2.0 1.8 5.1 3.2 1.5 .8
?

? is where I need a formula (row 3). Can someone help, before I pull the
rest of my hair out? What I am trying to accomplish is the calculation of the
the last six months. As you can see in the example above for the month of
October there is .8 already for the month. Now I need the worksheet to
automatically calculate the last six months which should total 14.4. Now if
we go back in time to August it should calculate the last six months which
would be 16. Hopefuly this explains it o.k., but if not let me know & try to
provide some more information. Thanks in advance!!!!

 

[RBall]

Hopefully this works. If not B-N is one row(1), Jan-Last Six Months is one
row(2) and 1.2-? is one row(3).

 

[RBall]

I lost patients & abandoned the project! Thanks anyway.