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Ollie had a think.
"Well, let me see... I know that 4 = 2 + 2. That's a good start!"
Have a go yourself. Try with the squares of the numbers from 4 to 20.
Once you have had some initial ideas, take a look at how three more of Flora's friends started the problem:
Did you find any square numbers which cannot be made by adding two prime numbers together? Why or why not?