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You Can Make Any Number Out of Four 4s Because Math Is Amazing (youtube.com)

Andrew Moseman, writing for Popular Mechanics: Here's a fun math puzzle to brighten your day. Say you've got four 4s -- 4, 4, 4, 4 -- and you're allowed to place any normal math symbols around them. How many different numbers can you make? According to the fantastic YouTube channel Numberphile, you can make all of them. Really. You just have to have some fun and get creative. When you first start out, the problem seems pretty simple. So, for example, 4 - 4 + 4 - 4 = 0. To make 1, you can do 4 / 4 + 4 - 4. In fact, you can make all the numbers up to about 20 using only the basic arithmetic operations of addition, subtraction, multiplication, and division. But soon that's not enough. To start reaching bigger numbers, the video explains, you must pull in more sophisticated operations like square roots, exponents, factorials (4!, or 4 x 3 x 2 x 1), and concatenation (basically, turning 4 and 4 into 44).

6 of 309 comments (clear)

  1. Re:Um, no. by XxtraLarGe · · Score: 5, Funny

    "and concatenation"
    No, that's not really maths,

    Oh really? Then how come "4" + "4" = 44? I just tested it in JavaScript, and it works!

    --
    Taking guns away from the 99% gives the 1% 100% of the power.
  2. Numbers are boring by Anonymous Coward · · Score: 5, Funny

    Except 5318008, naturally...

  3. Re:Um, no. by Anonymous Coward · · Score: 5, Funny

    Checkmate, atheists.

  4. Re:Um, no. by rickb928 · · Score: 1, Funny

    I quit my job at the McDonald's register 40 years ago to move on to what I was trained for, electronics repair.

    And concatenation is still not math. It's something else. Next thing you know, ALL Excel functions will be math. Calling your kitten 'biscuit' because it was born in the oven doesn't make it a biscuit.

    --
    deleting the extra space after periods so i can stay relevant, yeah.
  5. Re:BS detector went off and is overheating by Anonymous Coward · · Score: 2, Funny

    Well I think it's triangular, so there.

  6. Fourtran by Tablizer · · Score: 4, Funny

    In the spirit of Brainf*ck, I will use this to create a programming language called "Fourtran".