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I appreciate this may not be the correct forum to askt this on but wasn't sure where else to ask this. Does anyone have any reccommendations for how to begin working on such questions under time constraints:

786.3 * 1.03

684.9 * 1.07

78.2 * 2.04

Thanks for any help!

InvestingScientist
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  • Are you expected to have exact answers, or is an approximation good enough? Are you allowed pencil and paper? Just practice longhand computation. Because these are essentially 4 times 2 digits, they should not take long. How much time are you given? – Ross Millikan Sep 15 '20 at 20:52
  • @RossMillikan Sorry for not providing further detail. So it is multiple choice with 3 potential answers and pen and paper is not allowed - purely mental computation. This is type of question is part of a ten minute mental math test – InvestingScientist Sep 15 '20 at 20:57

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If you have three choices it should be easy. For the first, it has to have $9$ in the thousandths digit. It is just about $800$ because it is a $3\%$ increase over $786$. The fact that the second term is close to $1$ or $2$ makes it much easier-take advantage of that. Think first and last digits because they are the easiest to find.

Ross Millikan
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