1 + 2 + 1 = 4, which is 2 squared!
1 + 2 + 3 + 2 + 1 = 9, which is 3 squared!
1 + 2 + 3 + 4 + 3 + 2 + 1 = 16, which is 4 squared!
1 + 2 + 3 + 4 + 5 + 4 + 3 + 2 + 1 = 25, which is 25 squared!
1 + 2 + 3 + 4 + 5 + 6 + 5 + 4 + 3 + 2 + 1 = 36, which is 6 squared!
1 + 2 + 3 + 4 + 5 + 6 + 7 + 6 + 5 + 4 + 3 + 2 + 1 = 49, which is 7 squared!
Remember the formula for adding consecutive integers? Well, this trick is almost like a sequel to it! This time, you add all of the positive integers that are less than X twice! The total will always be equal to the square of X!
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© Derek Cumberbatch