Photograph by Bob Hope for the Daily Herald newspaper showing children at St Leonard's School, Warlingham, Surrey. One girl operates the large rule on the blackboard while the boy next to her studies a small hand-held version as the teacher looks over his shoulder. A slide rule is a type of simple 'analogue computer' consisting of graduated scales which can be moved in relation to one another to perform mathematical calculations. The most common use of a slide rule is to perform multiplication or division, based on logarithms. James Watson, Headteacher of St Leonard's, was in the news at the time for introducing 'New Maths' to the school curriculum. 'New Maths' meant learning through practical activities such as weighing, measuring and counting rather than reciting sums and times tables.
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