Since the dawn of civilisation, humans have used everyday materials to create mathematical models of the world around them. This album explores the ancient Greeks' astrolabe as a model of the skies; the sundial, to tell the time; Babylonian clay tablets to record wages and trading of sheep; wooden tallies for bulk-buying beer, the Incas' use of knots and string, and the sophisticated number-engine invented by Charles Babbage. This material forms part of The Open University course MST121 Using mathematics.