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Could you please explain to me why the answer of the equation $(24+3) - \frac{27}{3} \times 5$ is $-18$? How come it was negative when in my calculator it's postive?

Also this equation too, with a modulo problem: $12 \times 2 \div 3 \, \% \times 5$ and the answer is $3$ when in fact if you sum it up it's $1.6$. I’m so confused

gen-ℤ ready to perish
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hooely
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  • For the first, just follow the order of operations. Simplify the parentheses first to get $27-9\cdot 5$. Then compute the product to get $27-45$. Then compute the subtraction to get $-18$. Note that $(24+3)-(27/3)5\neq ((24+3)-(27/3))5$. It looks like maybe you multiplied both sets of parentheses by five instead of just the second set (if you did everything left-to-right, you'd have gotten zero, not a positive number, hence my expectation). – JMoravitz Oct 25 '17 at 15:25
  • As for the second, $(12\cdot 2/3)% 5 = (24/3)%5=8%5=3$. I do not see any interpretation that gives you $1.6$. – JMoravitz Oct 25 '17 at 15:28
  • @JMoravitz He thought % meant division – Anonymous196 Oct 25 '17 at 15:29
  • There are no percentage on my calculator so i used division – hooely Oct 25 '17 at 15:30
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    ...........Why? If you're cooking a cake and the recipe calls for sugar and you have none, would you use salt in place of it instead? – JMoravitz Oct 25 '17 at 15:31
  • @hooely the expression in the second question makes no sense as a "modulo problem". Please ask a separate question and clarify the context. – Alon Amit Oct 25 '17 at 22:41

1 Answers1

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For the first one you need to calculate the entire term start with the brackets, then multiplication and then you need to subtract one from the other:

So (24+3=27)-((27/3=9)*5=45)= 27 -45= -18.

The second calculation is you need to know what modulo means. In this particular case you need to calculate $(12\times 2 \div 3) \pmod 5$= 8%5. This means that you'll get a remainder of 3 when you divide 8 by 5.

Anonymous196
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