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No calculator, just some basic operations. Good luck!

(n^2-1)/(n-1) =(n+1)(n-1)/(n-1) =(n+1)

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Smart bitch!! Didn't thought of that!

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That's the way I used to solve it too...

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sharp as a tack

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(999^2)=998001 998001-1=998000 998000/998=1000 =1000

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mhh, lol, I didn't think of calculating 999^2 in my head ... I thought there must be a trick somewhere.

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doing it on scratch paper helps. I thought it was going to be a lot harder.

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There is a trick.

Hint: remember the formula for (a^2 - b^2)...

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To calculate ((999^2 - 1) / 998), we can simplify it step by step.

  1. Calculate (999^2): [ 999^2 = 998001 ]
  2. Subtract 1: [ 999^2 - 1 = 998001 - 1 = 998000 ]
  3. Now, divide by 998: [ \frac{998000}{998} = 1002 ]

Thus, the final result is: [ \frac{999^2 - 1}{998} = 1002 ]

Wtf, ChatGPT?!

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999

999(999-1)/998

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Waowho

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No paper, just in head...

Some easy facts:

1000*1000=(999+1)*(999+1)
999*1000=999,000
1000-999=1

The hard mental math:

999*(1000-1)=999,000-999=998,001

Ok, now it's obvious: (998,001-1)/998

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21,000,000

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Please do more of this :)

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I'll try to go for a daily puzzle then...

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<details> <summary> Click me </summary>

Potential answer

</details>

Testing collapsable answer... preview already tells me it likely won't work. Just making sure.

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Nice one! Do you like puzzles?

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I do.

My work is solving puzzles, basically :)

Outside of work, occasionally.

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I designed a graphic one. A pencil and paper "maze" puzzle. I was thinking about publishing it here on SN but wasn't sure. This is the first puzzle I see published here!

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6.4

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999^2/998 - 1/998

After checking a few numbers, I realized the greatest common divisor of 999 and 998 must be 1 since there is not much space between these numbers. So I give up.

Was fun to try to solve though, math exam flashbacks

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