the value obtained by multiplying each pair of numbers in a set and then adding the individual totals. For example, for the set of number pairs 2, 4
3, 5
6, 6
1, 4
the sum of cross-products is (2 × 4) + (3 × 5) + (6 × 6) + (1 × 4) = 8 + 15 + 36 + 4 = 63.