Math Tips and Tricks

On the SAT, there are two types of math troubles.  The “I don’t know how to do this” kind of problem and the “I don’t even know what the question is” kind of problem.  Since the SAT tests only Algebra, Geometry, and Algebra 2, most students have covered the content.  That means you do know how to do this.  The problem that many encounter is not being able to decipher the cryptic code of questioning on the Math test. 

I reserve a lot of these tricks for my private clients, but I will give you a tip from time to time right here in my blog.  Today’s tip is a little strategy I call “Make It A Real Math Problem.” 

There are n students who are failing Mr. Sampson’s biology class.  If that number of students was increased by p%, how many more students are now failing the class, in terms of n and p?

A) n + p

B) n - p

C) n + np

D)   np / 100

E) 100p / n

My head is already spinning.  I simply can’t wrap my head around the concept of all numbers that could be n or p.  But I can do it if I make it a real math problem. 

So here we go: “There are n students who are failing.”  How many students would you like that to be?  How about 10?  It’s a really hard class.  Also, 10 is a really nice number to use when we’re working a percent problem.  So n = 10.  Then the number of failing students is increased by p%.  What percent would you like to make that?  Let’s say it’s 30%.  So p = 30.  Now solve it.  The math is easy.  If I have 10 failing students and 30% more fail, how many more students are failing?  Our answer is 3.  Now we just have to plug our n and p values into our answer choices and see which one gives us an answer of 3. 

A)10 + 30 = 40   NO

B)10 - 30 = -20   NO

C)10 + (10)(30) = 310   NO

D)(10)(30) / 100 = 3  YES!

E)100(30) / 10 = 300   NO

Now isn’t that so much easier than trying to make sense of all those letters?  One last note on this strategy: you have to check all five answer choices. There is a possibility that, depending on the values you choose, more than one answer choice would work.  If that’s the case, try different values and check again.  That should leave you with only one.

Want the full scoop on all the Math tricks?  Sign up for private instruction with me.