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Help!

How would you solve 10 + 67 × 2?

I solved by putting a bracket between 10 and 67. Then multiplying by 2 Like this (10 + 67)2 = 154

However, others insist it's 144 and I'm wrong.

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    $\begingroup$ You multiply first, then add. This ambiguity is exactly why we use brackets. $\endgroup$ Aug 16, 2019 at 13:03
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    $\begingroup$ you do the multiplication first - so it's $67\times 5=335$, then $335+10=345$. $\endgroup$ Aug 16, 2019 at 13:04
  • $\begingroup$ See this Wikipedia article $\endgroup$ Aug 16, 2019 at 13:05
  • $\begingroup$ I think it's only natural one adds the bracket automatically considering the way the equation was written LRT $\endgroup$ Aug 16, 2019 at 13:07
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    $\begingroup$ Does $\ 10 + 67\, x\ $ or other polynomials also "cause ruckus"? If not, why? $\endgroup$ Aug 16, 2019 at 13:20

3 Answers 3

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You can't write $(10+67)\cdot 2$ (because you add a $10$ that doesn't exist), but if you want to use brackets, you can say: $(67+10)\cdot 2-10=67+67+10+10-10=144$. Or $10=5\cdot 2$: $2\cdot (67+5)=144$.

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If they meant $(10 + 67) \times 2$, they should have written that. Otherwise one should assume the standard order of operations is meant. Go to Wolfram Alpha and put in 10 + 67 * 2. It will answer 144 because there is nothing to indicate the addition should be done first.

Another possibility is that your friend is trying to create the next viral math formula. I suggest your friend should go back to the drawing board.

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First multiply, than add:

$$10+67\cdot5=10+335=345$$

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