What does $(vAj) mean?

[Asifaz]

Sum({<WH_AREA_NAME = {'Ambient'}, [Date Num]= {"$(vAj)"}, EXPCTD_ARRVL_DT_KEY=>}FINAL_DEMAND_FULFILLED_QTY/PACK_SIZE)

Sum({<WH AREA_NAME = {'Ambient'}, [Date Num] = {"$(vAj)"},EXPCTD_ARRVL_DT_KEY=>}Pull_Forward_Qty)

What does datenum mean here? Iwas told it was the max date of a week.

[LRuCelver]

[Date Num] is a field in the data model.

vAj is a variable in your app.

$(vAj) evaluates the variable and returns the result.

[qv_testing]

vAj - variable which you have created and you can see the defination of the variable 

$(vAj) - evaluates the variable and it gives the result.