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Chris Lele

New SAT Video: Exponents

Math Basics – Exponents

You are likely to see a few exponents on the SAT. In order to have a chance on the harder questions, you’ll have to first know your basics. Once you are consistent at doing well on these, you want have to worry about exponents. The thing, though, is it is very easy—especially during the stress of the actual exam—to make simple (and easily avoidable!) mistakes regarding exponents. So pay attention to the information below

Adding exponents

First try the following question:

5^10 + 5^10 + 5^10 = 5^n, what is the value of n?

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If you are thinking—that’s easy, it’s 30—think again. When you have similar bases (that’s the number below the exponent—in this case 5), you can’t just add the exponents. The thing is you really can’t do anything, besides simplifying the above equation to 2(5^10).

Multiplying exponents

Now try this question:

5^10 x 5^10 x 5^10 = 5^n, what is the value of n?

First, let me tell you the rule. When you multiply similar bases, in this case the number ‘5’, you ADD the exponents.

So the answer above is n = 30.

Here, try one more:

(x^5)(x^4) = x^n, what is the value of n?

In this question, the answer is n = 9, since we want to add, not multiply, the exponents.


About Chris Lele

Chris Lele is the GRE and SAT Curriculum Manager (and vocabulary wizard) at Magoosh Online Test Prep. In his time at Magoosh, he has inspired countless students across the globe, turning what is otherwise a daunting experience into an opportunity for learning, growth, and fun. Some of his students have even gone on to get near perfect scores. Chris is also very popular on the internet. His GRE channel on YouTube has over 10 million views. You can read Chris's awesome blog posts on the Magoosh GRE blog and High School blog! You can follow him on Twitter and Facebook!

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