In this article, Lindsey Fowler describes how an animal rhyme--that she shared with her fifth-grade students with the intention of assisting them with the concept of metric conversions--made fostering the Standards for Mathematical Practice (SMP) more difficult. The addition of animals, which added an extraneous element that students mistakenly…

Australia has used SI metric units for measurement for decades now, although the conversion of measurements from the earlier Imperial units--known as metrication--commenced subsequently in 1971, and was not completed until 1988. All Primary and Secondary schools were using only metric units in school lessons by 1973, and it became illegal to teach…

Plans are under way to redefine the International System of Units (SI) around 2018. The new SI specifies the values of certain physical constants to define units. This article explains the new SI in order to provide a resource for high school teachers as well as for advanced students already familiar with the pre-2018 SI.