This week’s year 6 mental arithmetic questions are all about measurements. They cover quite a few concepts, including using metric measures to measure. For example, to answer the question: Adam travelled 35.5 km by train and 500 metres by foot. How far in kilometres did he travel altogether? needs a knowledge of that 500 m is 0.5 km. This could be written as 36 km or 36 000 m. Another type of question found in this section is to compare metric measures and imperial measures. Whilst many people still use the old imperial units it is useful for children to know that there are just less than 2 pints in one litre and that an inch is about 2.5 cm. However, one day we may all use metric measures all the time and make it much easier for all our children to understand and use the system.