Greetings!
I’ve notice a fair amount of math that requires a calculator for achieving the answer.
Q: How many problems on the actual GRE will require us to calculate large number
factorials / square roots etc?
I’ve been using the microsoft math app on my phone which allows you
to “draw” or scan problems while practicing / taking quizzes etc. Its great for handling
factorials and roots. It will even break down the steps for a solution which has been helpful!
I also try to practice with the GRE calculator you have available (which is great!) but if I wanted
to solve this problem… how would I do it with the GRE calc?
Thanks as always for the assistance!
-B
Hello! When solving division factorial problems, you can remember how the factorial is written out to help you divide. For example, if I had 5!/3!, I wouldn’t need to actually multiply out each factorial like so: 5x4x3x2x1/3x2x1 - I can remember that 5! is just 3! with the additional x4x5. In the example, 30! is just 28! with the additional x29x30. Everything up to 28! will just cancel out, leaving us with (29x30)/2!, which is (29x30)/(1x2), which is 870/2, which is 435. Hope this helps!
Howdy!
Great explanation - thank you helps a lot!
I was familiar with the single factorials being divided like your 5!/3!.. being simple to ‘cancel out’
It was the multiplication of factorials in the denominator that was confusing me. After a couple more of these problems and following your example I think I’m getting the hang of it!
Thanks for your assistance really appreciate it!
-B