Dividing Fractions without a calculator

[Radioactive1112]

I started the AAMC chem question pack and one of the questions had me divide 7.58grams/286.14g/mol. Does anybody have any tricks for dividing fractions? I seem to get these things wrongs.

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[Cawolf]

Convert to scientific notation to have the easy division of 75.8 e -1/28.614 e1 = a little under 3 e -2 = just under 0.03.

Round, round round.

 

[NextStepTutor_1]

Round, definitely, if the numbers are close to easy numbers. 7.09 to 7, for example. But when it's not intuitive to round, I usually multiple both top and bottom by the same number to get rid of the decimals. For example, 7.25/11.75. Multiply both numbers by 4, and you get 29/47. Round to 30/50 and presto.
I typically avoid dividing by decimals so this is my go to. Scientific notation also makes big or small, or largely disproportionate, numbers easy to work with.

Hope this helps!

 

[sazerac]

You look at the answer choices, to decide how much you have to be accurate.

In your case, the answer choices were
0.025
0.25
1.00
2.25

C'mon man. This is 7 divided by some huge number in the high 200's. Is it more than 1 or less than 1? Less than 1. Is it a normal number, like a quarter? No, it's gotta be some microscopic number. *boom* 0.025 is your answer.

If you are dividing numbers on the MCAT you are doing it wrong. Ain't nobody got time for that. This question was not testing if you could get the right answer- this question was literally testing if you could throw out three dumb answers.