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problem
A little light thinking
Here is a machine with four coloured lights. Can you make two lights switch on at once? Three lights? All four lights?

problem
Summing geometric progressions
Watch the video to see how to sum the sequence. Can you adapt the method to sum other sequences?
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problem
Difference dynamics
Take three whole numbers. The differences between them give you
three new numbers. Find the differences between the new numbers and
keep repeating this. What happens?
