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Square Remainders
Age 16 to 18
Challenge Level 
If a number is even then it can be written in the form $2k$, where $k$ is an integer. Similarly, if a number if odd then it can be written in the form $2k+1$.
What can you say about the reminder when $a^2+b^2+c^2$ is divided by $8$ if $a, b, c$ are all odd?
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