Math CentralQuandaries & Queries


Question from Bobbi, a student:

try to put number 1 to 7 in seven circles (one in the middle, 3 on top, 3 below) so the numbers in each row of three circles--vertical, horizontal, and diagonal -- add up to 12. Each number can be used only once.

Hi Bobbi. List out all the ways you can add three different numbers (from 1 to 7) to get 12.

For example,
1 + 5 + 6
2 + 3 + 7

Order doesn't matter, but make sure you don't have any duplicates! You should find there are five possibilities in total.

Then look at the list and see which number appears most commonly. Put that in the middle circle, because the middle circle is used three times (two diagonals and the vertical) and the other numbers are used only twice each.

That should get you started!
Stephen La Rocque

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