Although number sense is difficult to define, it involves having a good intuition about numbers and their relationships, including the ability to have a "feel" for the relative size of numbers and to make reasonable estimations. Students with good number sense typically recognise the relative magnitude of numbers, appreciate the effect of operations on numbers and have developed a system of personal benchmarks. In this article the author discusses the concept of number sense, revisits a framework for examining basic number sense and shares activities and experiences to promote number sense, including examples from a lesson conducted with a Grade 5/6 class (aged 11-12 years). (Contains 1 table, 5 figures and 1 footnote.)