"Time-space as commonly understood, in the sense of the distance measured between two time-points, is the result of time calculation"

This quote by Martin Heidegger is talking about the idea of time-space and how it is frequently understood to describe the range between two points in time. Heidegger is recommending that this understanding of time-space is the outcome of estimations made about time, suggesting that our perception of time-space is heavily influenced by our measurement and quantification of time.