I have 20 rows of cells which contain a big formula.
Everything in the formula is constant except one variable.
That variable is read through alternate cells.
For example
frist cell contains = AVERAGE(A$6:$AT$102)
Second contains = AVERAGE(C$6:$AT$102)
Third contains = AVERAGE(E$6:$AT$102)

when I try to drag the cells the above three equations always contain the same first variable instead of it changing with each cell.
Can some one help ?

Thanks