automatically Sumarize headcount based on table

[oblix]

I have a register that the daily head count is reflected on per department and for each day.
The manager wants a report to summarize this information per department.

The table looks like this as an example:

Morning Head Count
Department	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30	31	32
A	100	100	100	100	100	100	100	100	100	100	98	98	80	15	15	81	99	99	99	99	99	99	99	99	99	99	100	100	25	25	30	16
B
C
D
E
F

I would like to sumarized like this:

Summary

Department A

From the 1st to the 10th = 100

From the 11 to the 12th = 98

For the 13th = 80

From the 14th to the 15th = 15

the summary result will be diverent everytime and can not be fixed to certains dates but rather as the amount differ over those dates.
dont know if this can be done by means of formula or vba
can any one assist pls

 

[oblix]

Sorry in my example I went to day 32 by mistake as a month only has 31, 30, 29 or 28 days.