9 thoughts on “Today’s Reading Assignment On “The Great Stupid”: 2+2=5

  1. Oh. My bad. (That was sarcasm.)
    It was John R. Lewis, not John L. Lewis. You know: God.
    But since 2+2=5, it’s all OK. It is what it wasn’t. God Understands.

  2. When I first started reading, I thought the obvious tactic would be to redefine the symbol “5” to mean the number four, because of course any form of language relies upon conventions to convey meaning. Such redefinitions, of course do nothing to challenge or elucidate the underlying idea being communicated, they simply thwart attempts to communicate it, which is exactly Sexton’s point.

  3. Jack wrote, “The advocates of 2+2=5 are among the anti-Americans Joe Biden and the Democrats are courting as allies in their effort to upend traditional American values, weaken democratic institutions, and install a system of favored races, genders, and ideological indoctrination.”

    In my opinion what’s happening in the United States right now is a very intentional bastardization* of an entire culture in an effort to fundamentally shift society away from a Constitution based free society towards dictatorial totalitarianism. The only way to accomplish this is to fundamentally destroy the existing culture in the minds of the masses by demonizing absolutely everything that built it, it’s all evil, and gradually replace that evil culture as you go with propaganda based psychological indoctrination, aka brainwashing!

    *Bastardize: change (something) in such a way as to lower its quality or value, typically by adding new elements.

  4. A couple more links for the.”critical mathematics”..pile.
    https://mathedcollective.wordpress.com/2020/07/09/attack-on-brittany-marshall/

  5. 2+2=5 *but only* for sufficiently large values of 2 and sufficiently small values of 5.

    So only in very esoteric contexts, such as when 2.49999999999999999999999999999999999999 is represented as 2, and 4.99999999999999999999999999999999999998 is represented as 5, the kind of thing that happens when converting 64bit IEEE floating point and 32bit VAX floating point format to give an unsigned integer result.

    Numerical analysts have to be aware of such things when doing really high precision repeated arithmetic operations in heterogenous environments. You don’t round till the end.

    There are other even more abstruse cases in number theory, but in the usual arithmetic system we use, where the addition operator is reflexive, symmetric, and transitive, commutative (a+b = b+a for example), 2+2 = an integer between 3 and 5 exclusive.

    Even that isn’t true in “bankers rounding”.

    https://support.mindbodyonline.com/s/article/203274703-Why-isn-t-my-sales-tax-rounding-up-Banker-s-Rounding?language=en_US

    MINDBODY uses something called Banker’s Rounding. It’s a commonly used method for rounding taxes. Rather than rounding 0.5 and higher up, and 0.4 and lower down, bankers rounding rounds 0.5 to the nearest even number. Essentially if the cent value of the tax total is odd, the 0.5 (half-cent) rounds upwards; If the cent value is even, the half-cent rounds it downwards. Here’s an example:
    A business owner has a 6.5% tax rate. Due to banker’s rounding, a $1.00 transaction will ring up as $1.06 instead of $1.07:

    A $1.00 X 6.5% tax= 0.065. If you look at the 0.065 in the terms of dollars and cents, this is 6.5 cents. Because the six is in the cents place and is an even number, Banker’s rounding determines that 6.5 cents will be rounded down to six cents. Therefore, we add six cents to our $1.00 charge= $1.06 total sale including tax.

    Additional examples that would determine whether the tax would round up or down:

    A $15.00 sale X 7.5% tax = $1.125 ß Because the two (the middle number after the decimal) is in the cent place and is even, this value would round down to the nearest even cent, which would be $1.12 in sales tax. Making the sale $15.00 + 1.12= $16.12 total.
    A $15.00 sale X 8.5% tax = $1.275 ß Because the seven (the middle number after the decimal) is an odd number, this value would round up to the nearest even cent, which would be $1.28. Making the sale $15.00 + 1.28= $16.28 total.

    Situations where Banker’s rounding wouldn’t apply

    Banker’s rounding isn’t applied if the cents in thousandths ($0.001) place doesn’t end in the number five. In this scenario, normal rounding rules apply.

    For example:

    A $1.00 sale X 6.7% tax = $0.067. Bankers rounding doesn’t apply because the last number is 7, instead of 5, so this value will follow normal rounding rules and round up to a tax amount of $0.07.
    A $15.50 sale X 6.7% tax = $1.0478. Since the last number in the cents ends in 8, instead of 5, Banker’s rounding does not apply and normal rounding rules kick in to round up the tax amount to $1.05.

    TLDR; 2+2=4
    (except when it doesn’t, 2+2=11 in trinary notation for example)

    • The purpose of Banker’s Rounding (this is the first time I’ve heard it called that, BTW) is so that the addition of many such “x.5” numbers after rounding will more closely approximate the sum of those same numbers before rounding.

      Basically, at that dead-in-the-middle case, you round half of them up and half of them down. It’s arbitrary, but it has validity.

      –Dwayne

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