Can any body help me

I have these 2 formula

ToNumber (GroupName ({HotelSum > 75.Rate}))

And then i use the formula above in this formula

IF ({HotelSum > 75.Rate}) = {@Group header to number} And {HotelSum > 75.L/P} = "P" Then 1 Else 0

My plan was to sum up this formula so it would tell me how many booking i had at a certain rate.
If i right click on this formula when its in my detail area there is no options to summarize and if i try a formula to summarize it i get the message " The Summary / Running total field could not be created" "This field could not be summerized".

can any body shed any light on how i could summarize this up or how i could re-write these formula to be able to summarize