Help with excel please!

I'm trying to set up worksheet to help calculate the height and GPE of a rocket (and the KE but that doesn't matter ATM)

Each time a weight is added .0010575 kg is added, I'm trying to get it to add that incrementally.

So the first 3 cells should just be the rocket weight, then the next three down should show the rocket weight plus the .0010575 kg added, and after that add .0010575 (and on).

This is the formula I worked out that should work, but doesn't do what I want.

=0.00715+(FLOOR((CELL("row",E2)-2),3)*C$23)

Whic is the rocket weight+ the row number of the cell minus 2, rounded to the nearest multiple of three, times the extra weight.

Where e2 is the same cell as the one the formual is in and c23 is the extra weight added. Note that I have titles above the cells.

It give results that are not what I wanted, I'm sure it means well but it isn't working. Any one know whats wrong?

Let me see if I get this right...

The first three cells should just have the rocket's mass, correct?

Then, the next three cells should have the rocket's mass + 1 ballast mass?

Then, the next three cells should have the rocket's mass + 2 ballast masses?

Why do you need the value repeated three times?

It's part of a school experiment so to get a fair/good average we did 3 at each catogory. The ballast is a 10 gram weight plus the selotape used.

If your talking about the formula (I'm not sure) where do I repeat something?

Well, looking at it, I don't see any reference to any data besides C23. The "Cell" function is giving you the actual row number of the cell, not an external data value. So, the value of "CELL("row",E2)" is actually "2"

Is that what you want?

Yup. The way I think I have it riged is it changes that 2 to 0 and then multiplies it by the additional weight. The minus two should take into account the title and making the floor function work as I want it two (so it takes e3 down to 0 rather then leaving it at 3). In e14 it takes 14, takes two making it 12, [editcarrying on my train of thought after it stopped of at common sense station) to the nearest multiple of three making it 12, which I should have divided by three. Crisis averted.