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One offs. WMA Number and algebra. Michael Drake School of Educational Policy and Implementation. Starters. Write the next three terms of the sequence 3, 6, 9, 12, …. Write a sentence explaining how to get from one term to the next. Start with “To get the new term …”. 3 6 9 12.
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One offs WMA Number and algebra Michael Drake School of Educational Policy and Implementation
Starters • Write the next three terms of the sequence 3, 6, 9, 12, … Write a sentence explaining how to get from one term to the next. Start with “To get the new term …” • 3 • 6 • 9 • 12 Down rule Across rule
Starters • Think of a number • Add 3 to it • Double it • Subtract two • Halve it • Subtract the number you started with • Add 6 • Multiply the number by 3
Think of a number… • How do we write down that we are thinking of a number – without giving away the number we are thinking of? • What would one more than the number look like? • What would 3 less than the number look like? • What would double the number look like?
Starters What is? 2 4 3 3 52 6 4 6 6 5 7 7 7 8 6 102 9 11
Does this always work? Try some examples of your own… • How many examples do we need to convince ourselves if it works? • What sort of examples do we need to try? • What examples did you try and did it work?
How about… • 29 31? • 299 301? • 4. 01 3.99?
How does it work? • Let’s look at the structure underneath the problem by examining an example and copying it 4 4 3 5 What letter shall we use to show the number we are starting with? n - 1 n + 1 n n
n +1 n n2 +n -1 -n -1 Which is n2 – 1 (so one offs are always one less than the square number)
Does it generalise? • Predict the answers to these problems • 27 33 • 3.8 4.2 • n2 – 16