Here is a pattern that grows: 4, 7, 10, 13 … What would the 100th number be? And is there a way to know without writing out all one hundred of them?
You are not expected to know this yet. By the end of today you will be able to answer it. This is the last algebra lesson of primary school, so today we pull together three big ideas from the year: patterns, expressions and equations.
Two function machines are on screen. Together we will work out what the forwards machine does to each position in the pattern 4, 7, 10, 13, then how the backwards machine finds a position from a known value. Watch each step of the working.
Today we work through one full challenge together. We take it one stage at a time. First we look at the pattern 5, 9, 13, 17. Then we say its rule in words. Then we write it as an expression. Finally we set up an equation to find which position gives 61.
In your maths copy, work the sample challenge through its stages and label each one as you go:
Then check your solution by putting it back into the rule.
A five-stage algebra mystery. Solve each stage to unlock the next:
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