Hello SterlingM

Welcome to Math Help Forum!No. is true (value = 1) for just 4 values: when the sum of all three inputs ismore than1. See the attached truth table.

No. is also true for just 4 values."S= exclusive OR of inputs C0, X0, X1."

And this one will also have 6 true values?

In the truth table, I've put in an extra column to show the value of XOR , before XOR-ing this with to give the final value of .

Grandad