median
don steward
mathematics teaching 10 ~ 16

Tuesday, 7 December 2010

hard haitch using 1 to 7

hard haitch
use 1 to 7 so that the (four) lines of three all add up to the same number
prove that 4 must go in the middle and the only possible total is 12


there are three solutions but these involve switching numbers within the lines of three

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