I have 3 columns in excel one contains words, one contains letters and one
contains numbers. I want to add the numbers when the word in column one and
the letter in column two are to values I've set.

I'm using the following formula, but keep getting a syntax error:
=SUMPRODUCT(--($J$33:$J$51="Core");--($M$33:$M$51="M");$L$33:$L$51)