Boolean Algebra Worksheet - Digital Circuits - All About Circuits Question 4 The following set of mathematical expressions is the complete set of “times tables” for the Boolean number system:. $$0 × 0 = 0$$ $$0 \ x \ 1=0$$ $$1 \ x \ 0=0$$ $$1 \ x \ 1=1$$ Now, nothing seems unusual at first about this table of expressions, since they appear to be the same as multiplication understood in our normal, everyday system of numbers.