17 thoughts on “Use your brain…”

  1. It is sad that this type of thing isn’t so trivial for everyone that it would never be posted. I guess lots of people somehow forget the order of operations their teachers tried to teach them.

  2. Carter, I got the same answer as you but it seems too obvious. I’m wondering if they don’t know the order of operations and think that the x 0 would apply to everything before it, making the answer 4?

  3. Back in the early 50s, my dad used to talk about how he was the best in his class at what they called “mental math” in which a teacher would reel off a string like, say, 3 plus 2 minus 4 times 3 plus 9 divided by 4 . . . etc. and the kids were supposed to be able to keep a running tally to determine the final answer without even a thought about order of operations. Maybe that was what this was supposed to be like, or trying to catch people who learned like that?

  4. What am I missing here? You times anything by zero, you get zero, right? So my answer would be 4. Anything before the 2+2 equaling 4 would be zero. So I say 4 is the answer.

  5. Bob and Jose, you forgot about the order of operations (or maybe you never learned it)
    The order in which operations should be done is abbreviated as PEMDAS:
    Parentheses.
    Exponents.
    Multiplication and Division (from left to right)
    Addition and Subtraction (from left to right)

  6. depends if you use the order of operations (i.e. “written” math) or the “mental” math Lynda describes. If you are given a string of operations it’s usually implied that each new operation works on the result of the previous – simply because it’s nearly impossible to mentally use “multiplication/division before addition/subtraction”, not to mention ( and )

    oh, and then in some rare versions of “written” math there are different orders of operation for different multiplication signs (the “x” variant used here, the “dot operator” ⋅ or the asterisk * – not to forget the implied multiplication sign in “2a”)

  7. I know you are all in the USA and that you do many things differently there, spelling for instance, oh, and pronouncing herb as erb but not hospital as ospital (how we laugh at you).
    The real way of doing maths (yes, it’s not called math at all) gives the answer to the above problem as 79, which is correct. However, if you put brackets around, let’s say the 25 – 0, then the answer becomes 104, you can use that as a reason you got it wrong if you want, as long as you remember that the real answer is 79.
    If you insist on using a calculator then (sigh) it’s 50 plus 50 (push total, that’s the equal sign) that gives you 100, the subtract 25, push total, that gives 75, now multiply by 0 (!) which gives you 0, now add 2, which gives you 2, and now add two again, which gives a total of 4, so 4 is your answer if you use a calculator.
    Oh, if you don’t push total every time, you get 104 on the calculator.
    However the answer is still 79.
    Because….
    50 plus 50 is 100, minus 25 is 75, times nothing is still 75 (because you’re multiplying it no times), plus 2 is 77, plus 2 is 79.
    Jeez, I have to explain this stuff to you ?

    • Wait… what?! You guys don’t use the anything multiplied by zero is zero rule? I can’t grok this.

      I looked at the problem programmatically because that’s the only correct answer. 104 got us to the moon, with 4 the rocket would have exploded. I don’t know where 79 would have taken us.

      Anyways… we all know the correct answer is 42. 😉

  8. “50 plus 50 is 100, minus 25 is 75, times nothing is still 75 (because you’re multiplying it no times), plus 2 is 77, plus 2 is 79.”
    It’s not “times nothing”. It’s times ZERO, which results in ZERO.

  9. WTF? 79? 4?
    It’s 104, just follow operation order and it will come right. First, do 25×0 = 0 (multiplication has higher precedence than adding or subtracting), then do the rest of the operations (additions and subtractions have the same precedence), from left to right.
    50 + 50 – 0 + 2 + 2 = 104
    It’s really sad that this kind of basic math isn’t trivial to everyone 🙁
    In my country, this is taught to 9 year old kids.

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