Formula to multiply column with a dynamic column

I have created a formula to multiply 2 columns (one with prices and one with numbers)
Only there are multiple columns with number (multiple months), so how can I create formula with a dynamic column?

I have created an example
So if I change the month in cell K1, it should multiply the number of the new month times the prices
I tried to make the formula dynamic with an index function but it did not work out.

Hope somebody can help me

=SUMPRODUCT(($I$2:$I$9)*INDEX($B$2:$G$9,,MATCH(K$1,$B$1:$G$1,0)))
Try the above formula

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