Following Frege, the mathematical expressions “\(1+4\)” and “\(2+3\)” have the same denotation but different senses. Frege did not actually say what a sense was, though it was clear that, somehow, sense determined denotation. Earlier we talked of computations associated with “\(1+4\)” and “\(2+3\)”, but what we presented was quite simple-minded. Tichý introduced the idea of a construction with these two expressions prescribing different constructions. A much more formal version of this appears in a series of papers, (Moschovakis 1994; Moschovakis 2006; Kalyvianaki and Moschovakis 2008), all of which trace back to (Moschovakis 1989). In these is a very sophisticated formalism in which the sense or intension of an expression is an algorithm, and algorithm execution determines denotation. In what follows we sketch the ideas, skimping on most technical details.