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The Big Reveal

Okay, the answer from yesterday’s post is…

(DRUMROLL PLEASE)

5050

How did he get that?  Well, he did not start by adding 1 + 2 + 3 + …  Instead, he found a pattern.

Try writing 1 to 100 on one line and then 100 to 1 on the next.  Add up the numbers directly up or down from each other.

1 + 100, 2 + 99, 3 + 98, 4 + 97, 5 + 96, …

Each sum is 101, and you get 100 of these sums which comes out to 10100.

You need only half this amount, as you added each number in twice.

10100 / 2 = 5050

How about you?  Did you get the answer?  Whether you did or did not, what did you try?

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