Headcount Forecast

[#1]

I got the above figured out... but not the following.. can someone help pls?

basically-- I have the Active Headcount for Match as well as Future Joiners/Leavers/Open roles for the next 12 or so months.. and from that create a forecast

Active Next Month = Active This Month+Future Joiners+Open Roles- Future Leavers

and as attached is my qvw

Headcount   Drivers	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	Jan	Feb	Mar	Apr	May
Active This Month	1401	1401	1369	1341	1333	1326	1329	1338	1342	1346	1351	1368	1369	1370	1371
Future Joiners	0	0	0	0	0	0	0	4	5	17	1	1	1	1
Future Leavers	32	28	8	7	0	0	0	0	0	0	0	0	0	0
Open Roles	0	0	0	0	3	9	4	0	0	0	0	0	0	0
Active Next Month	1401	1369	1341	1333	1326	1329	1338	1342	1346	1351	1368	1369	1370	1371	1372

[#2]

here is my qvw