Leah4sciMCAT I eventually figured it out but it was kinda tougher to just know that 1/3 could represent that fraction 35/103 -33/100 in your first example. I would have tried to just divide them :,(
When it comes to MCAT Math, rounding is always your best friend! I would round the decimal number in the denominator to something that I can work with more easily. If I round 16.7 up to 18, then I am left with 6/18. Which further simplifies to 1/3 or 0.33. On the calculator, 6/16.7 equals 0.359, so I would say our estimation is pretty close!
What I don't understand is how you get 3/4 for the last problem. Wouldn't it be 3M over 4r Squared? I guess I need more explanation with the missing step to just get simplified 3/4. I am missing something. How did you get rid of the M on the top and the r squared on the bottom?
Thanks for reaching out! In this problem, we are comparing the gravitational force on earth (simplifies to m/r^2) to the gravitational force on the other planet, which is ¾ of m/r^2. We’re not really concerned with cancelling out the m and r^2, so much as we are with comparing the two values. The planet’s gravitational force is ¾ the size of that on earth. That is the ratio we are looking for. Hope that cleared it up for you!
Do you happen to have a chart for the orbitals? For some reason, I have a hard time grasping the concept that sp^3d is 5 orbitals. It's just little things like this that confuse me that cause my C/P score to be a lot lower than it should be. Thanks so much!!
Thanks for watching and asking! I don’t have a chart for the hybrid orbitals, but think about it like this: An sp3d hybrid orbital is made by the hybridization of 1 s orbital, 3 p orbitals, and 1 d orbital. Put it all together, and you have sp3d. For more on hybridization for the MCAT, visit leah4sci.com/mcat-chemistry-hybridization-review-for-sp3-sp2-and-sp/
alaintennis 100 is just a suggestion. For something like 145/725 I would consider other close numbers, for example. 145 up to 150 and 725 up to 750. Now divide out the 50s giving you 3/15 or 1/5 = 0.2.
Leah4sciMCAT hey so when you rounded 145 to 150 that made sense to me but then you rounded 725 to 750, is it because they both have to have 50 to make the math more accurate?
for such problems, i'd suggest converting them back to scientific notation, So for 1/1500,000 => 1*10^0/ 1.5*10^6, then we can do 1/1.5 * 10^0/10^6 this is now easy to solve: we do it in 2 parts = 1/1.5 is just 1/3/2 = 2/3 = 0.667 10^0/10^6 = 10^ -6. So our ans is 0.667*10^-6 => 6.7*10^-7.
Late as hell lol, but it might help someone looking at the comments. You could separate it into: ((1/1.3) x (1/100)) 1/1.3 is more than 0.5, but less than 1. So we could estimate 0.8 0.8 x 1/100 = 0.8/100 = 0.008. The calculator gives 0.0077
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Leah!!! Thank you! You're the best.
Awww, you're welcome!
You’re amazing, thank you!
You're welcome! :)
How about a smaller numerator and larger denominator value? Such as, 7.15/286.14
round this to 7/(28x10) 7/28 simplifies to 1/4 or 0.25 which comes to 0.025. Calculator says 0.02499 which is close enough
These are helpful videos. I appreciate the step-by-step process for teaching the tips and tricks. Thank you.
You're welcome
I dont get how you got 1 and 3 for the fraction in the first example :(
At which point of the video please?
Leah4sciMCAT I eventually figured it out but it was kinda tougher to just know that 1/3 could represent that fraction 35/103 -33/100 in your first example. I would have tried to just divide them :,(
What is a good trick to use for something like 6/16.7 on the worksheet?
When it comes to MCAT Math, rounding is always your best friend! I would round the decimal number in the denominator to something that I can work with more easily. If I round 16.7 up to 18, then I am left with 6/18. Which further simplifies to 1/3 or 0.33. On the calculator, 6/16.7 equals 0.359, so I would say our estimation is pretty close!
hey these math videos are still applicable for the newer mcat right? (since they changed it in 2015?)
Yes of course, math shortcuts are math shortcuts and therefor don't change
What I don't understand is how you get 3/4 for the last problem. Wouldn't it be 3M over 4r Squared? I guess I need more explanation with the missing step to just get simplified 3/4. I am missing something. How did you get rid of the M on the top and the r squared on the bottom?
Thanks for reaching out! In this problem, we are comparing the gravitational force on earth (simplifies to m/r^2) to the gravitational force on the other planet, which is ¾ of m/r^2. We’re not really concerned with cancelling out the m and r^2, so much as we are with comparing the two values. The planet’s gravitational force is ¾ the size of that on earth. That is the ratio we are looking for. Hope that cleared it up for you!
Do you happen to have a chart for the orbitals? For some reason, I have a hard time grasping the concept that sp^3d is 5 orbitals. It's just little things like this that confuse me that cause my C/P score to be a lot lower than it should be. Thanks so much!!
Thanks for watching and asking! I don’t have a chart for the hybrid orbitals, but think about it like this: An sp3d hybrid orbital is made by the hybridization of 1 s orbital, 3 p orbitals, and 1 d orbital. Put it all together, and you have sp3d. For more on hybridization for the MCAT, visit leah4sci.com/mcat-chemistry-hybridization-review-for-sp3-sp2-and-sp/
How would you go about dividing 145/725. It's hard to bring 725 to 100. Had this in a practice problem.
alaintennis 100 is just a suggestion. For something like 145/725 I would consider other close numbers, for example. 145 up to 150 and 725 up to 750. Now divide out the 50s giving you 3/15 or 1/5 = 0.2.
Leah4sciMCAT hey
so when you rounded 145 to 150 that made sense to me but then you rounded 725 to 750, is it because they both have to have 50 to make the math more accurate?
What about 1/large numbers, say 1/1,500,000? As ive come across in a practice problem.
What about them specifically?
for such problems, i'd suggest converting them back to scientific notation,
So for 1/1500,000 => 1*10^0/ 1.5*10^6, then we can do 1/1.5 * 10^0/10^6
this is now easy to solve: we do it in 2 parts =
1/1.5 is just 1/3/2 = 2/3 = 0.667
10^0/10^6 = 10^ -6.
So our ans is 0.667*10^-6 => 6.7*10^-7.
How would you go about dividing 1/130?
which part/point of the video are we referring to?
Late as hell lol, but it might help someone looking at the comments.
You could separate it into: ((1/1.3) x (1/100)) 1/1.3 is more than 0.5, but less than 1. So we could estimate 0.8
0.8 x 1/100 = 0.8/100 = 0.008.
The calculator gives 0.0077
33 multiplied by 3 is 99
which is approximately 100
She means that 33 can go into 100, 3 times. Because 33+33+33=99 which we can round to 100.
Correct, and so we get 3 '33s' in 100