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Here are some simple math tricks I have used on quant that helped shave off 10 seconds here and 20 seconds there which could come in handy granting you an extra minute or two that could make or break your QA
Ok, well the first one that saves me the most time would be rounding numbers up or down to make the calculations easier and more mental, example if I am given 86 x 73 sure I can sit there and multiply it out, or I can just turn that 86 into a 90 and that 73 into a 70 then it becomes a simple 9 x 7 calculation in your head then you add the two zeros and if you are wondering about being super off, you wont be 86x73 is 6287 while 90 x 70 is 6300. I mean you are only 13 numbers off, you arent going to be given answers that are this close together, rarely does that happen. You will be surprised at the amount of time you save especially if you have to do multiple calculations.
another trick I use for squaring large numbers between 30 and 70 would be this, say you are trying to square 43^2 again I can sit there and multiply it out but what if you do this. for any number between 30 and 50 take that number and subtract it from 50 so that 50-43 is equal to 7 now take that 7 and subtract it from half of 50 so 25-7= 18 there are your first two digits, for second two digits, take the 7 and square it, 7^2 = 49 so your answer is 1849, the explanation for this is longer than it takes you to mentally do it. lets do another example where the number is 38^2 so again 50-38 = 12 and 25-12 = 13 now we square twelve and get 144 so we have 5 digits, but thats no problem, we take the 13 and add the 1 from the 144 to the three so we get 14 then we write the last two digits 44 so answer would be 1444. for numbers above 50, you use the same rule but instead of subtracting the difference from 25 you add the difference to 25 so here is another quick example 53^2 so 53 is 3 above 50 now we take the 3 and add it to 25 so we get 28 then we take the 3 and square it, we get 9 again we need 4 digits, so first 2 are 28 and last two are 09 so answer is 2809. when you practice all these, youll realize that you are taking what could be a 20 second calculation for someone and turn it into an 8 second one.
If you are wondering about my score, I got a 96 percentile with 3 99s in bio, chem, and QA. Not so hot on my verbal and RC.
If this can help one person out, I will be satisfied.
Ok, well the first one that saves me the most time would be rounding numbers up or down to make the calculations easier and more mental, example if I am given 86 x 73 sure I can sit there and multiply it out, or I can just turn that 86 into a 90 and that 73 into a 70 then it becomes a simple 9 x 7 calculation in your head then you add the two zeros and if you are wondering about being super off, you wont be 86x73 is 6287 while 90 x 70 is 6300. I mean you are only 13 numbers off, you arent going to be given answers that are this close together, rarely does that happen. You will be surprised at the amount of time you save especially if you have to do multiple calculations.
another trick I use for squaring large numbers between 30 and 70 would be this, say you are trying to square 43^2 again I can sit there and multiply it out but what if you do this. for any number between 30 and 50 take that number and subtract it from 50 so that 50-43 is equal to 7 now take that 7 and subtract it from half of 50 so 25-7= 18 there are your first two digits, for second two digits, take the 7 and square it, 7^2 = 49 so your answer is 1849, the explanation for this is longer than it takes you to mentally do it. lets do another example where the number is 38^2 so again 50-38 = 12 and 25-12 = 13 now we square twelve and get 144 so we have 5 digits, but thats no problem, we take the 13 and add the 1 from the 144 to the three so we get 14 then we write the last two digits 44 so answer would be 1444. for numbers above 50, you use the same rule but instead of subtracting the difference from 25 you add the difference to 25 so here is another quick example 53^2 so 53 is 3 above 50 now we take the 3 and add it to 25 so we get 28 then we take the 3 and square it, we get 9 again we need 4 digits, so first 2 are 28 and last two are 09 so answer is 2809. when you practice all these, youll realize that you are taking what could be a 20 second calculation for someone and turn it into an 8 second one.
If you are wondering about my score, I got a 96 percentile with 3 99s in bio, chem, and QA. Not so hot on my verbal and RC.
If this can help one person out, I will be satisfied.
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