Formula to multifly 2 cells for 400 rows

[rizmomin]

Hello:

Please refer to attached file.

I need a formula in Cell P2,T2,X2, (every 4th column) to do the following:

P2= (P6*$F6)+(P7*$F7)+..........................(P398*$F398)

Either a formula or VB code would work for me.

Let me Know if you have any questions.
Thanks.

Riz