Home




Exponents Lead to Cumbersome, Time-Consuming Calculations involving Large Numbers but it is Pattern-Driven

GMAT ExponentsThe GMAT's quantitative section is increasingly emphasizing problem solving skills over calculation abilities, and often does so in the form of "Number Properties" questions. The authors of the exam are also quite adept at recognizing "mathematical psychology", and creating questions that increase an examinee's anxiety by enough to make that process of problem solving a bit more difficult. One of the major themes that arises as a result is the use of exponents, which carry with them a number of properties extremely useful to the writers of the GMAT.

Exponents

• Inspire fear (or at least apprehension) in test takers
• Lead to cumbersome, time-consuming calculations involving large numbers
• Are actually quite pattern-driven, and reward those who seek out those patterns rather than attempt to perform the extensive calculations

How can this help you on the exam?

If you embrace the pattern-driven quality of exponents, you can rest easy on exponent questions involving large numbers, knowing that you can test the pattern with small numbers, and simply extrapolate it to solve the overall question. Take, for example, a question that asks:

What is the sum of the digits of 10^25 - 37?

Listing out the numbers will be time consuming and contains the potential for error (counting to 25 when writing out the zeroes, then writing out that many digits in the difference, is a tedious process). But if you recognize that the first number will simply be "1" followed by 25 zeroes, and that the difference of the two will end in 63, preceded by a series of 9s, you can make quick work of this problem.

Try using a smaller exponent to see what the result will look like:

10^4 - 37:

10000
- 37
9963

If the exponent is 4, we end up with 4 digits in the answer: a 6, a 3, and the rest are 9s. Trying again with another exponent, we can see that the pattern holds for any exponent:

10^6 - 37:

1000000
- 37
999963

Again, we have the same number of digits in the difference as the value of the exponent, and two of those are 6 and 3, with the others 9s.

So, we can conclude that 10^x - 37 will give us a solution in which we have (x-2) 9s, a 6, and a 3.

Because 6+3 is 9, the sum of the digits will be (x-2) * 9 + 9, or (x-1) * 9.

In the original example - 10^25 - 37, the exponent is 25, so we'll have (25-1) * 9, or 24*9, and the answer is 216.


Prepare with Veritas Prep: Get GMAT 700+

Option 1: Live GMAT preparation with the Best Instructor from any part of the world
Option 2: Prepare at your own pace with On-Demand GMAT Preparation
Option 3: Private GMAT Tutoring

Author : 

Veritas PrepVeritas Prep is the world’s largest privately-owned GMAT preparation and admissions consulting provider, offering industry-leading programs to help applicants improve their test scores and gain admission to the world’s best graduate schools. Founded in 2002 by graduates of the Yale School of Management, Veritas Prep is now live in more than 90 cities worldwide, as well as interactive online courses  available everywhere. Additionally, Veritas Prep offers industry-leading admissions consulting services for applicants seeking admission to the most competitive business schools, law schools, and medical schools in the world.

Essential GMAT Reading Comprehension Guide


After reading F1GMAT’s Essential GMAT Reading Comprehension Guide, you will:

1. Complete GMAT RC Questions in less than 1 minute and 50 seconds
2. Read Faster
3. Take Notes Effectively
4. Collect and Interpret Facts
5. Speed up Summary Creation
6. Remember Information
7. Question the Author   
8. Learn to Answer GMAT Reading Comprehension Title question   
9. Learn to Answer GMAT Reading Comprehension Main Idea Question   

10.Learn to Answer GMAT Reading comprehension Inference question

11. Learn to Answer GMAT Reading Comprehension Detail Question   

12. Learn to Answer GMAT Reading Comprehension Purpose Question
12. Learn to Answer GMAT organization of passage Question
13. Learn to identify the style/tone or attitude of the author

Download Essential GMAT Reading Comprehension Guide (2019 Edition) (100+ New Questions)









Mastering GMAT Critical Reasoning



After you read F1GMAT’s Mastering GMAT Critical Reasoning Guide, you will learn:

How to overcome flawed thinking in GMAT Critical Reasoning?  


How to spot Inconsistencies in Arguments  

How to eliminate out of scope answer choices using Necessary and Sufficient Conditions  

How to Paraphrase GMAT Critical Reasoning Question  

How to Answer Assumption Question Type  

How to Answer Conclusion Question Type  

How to Answer Inference Question Type  

How to Answer Strengthen Question Type  

How to Answer Weaken Question Type  

How to Answer bold-faced and Summary Question Types  

How to Answer Parallel Reasoning Questions  

How to Answer the Fill in the Blanks Question


Download Mastering GMAT Critical Reasoning (2019 Edition) (25+ New Questions)




Navigate F1GMAT


F1GMAT Services (MBA Applicants) 


F1GMAT's Books

MBA Salary(Latest Salary Data)
 
MBA Admission Interview Tips

Funding 

Deadlines

MBA Application Essays


MBA Recommendation Letter

GMAT Tutorials

GMAT Question Bank

Top MBA Programs

Get F1GMAT's Newsletters (Best in the Industry)
Included in the Newsletter:

  • Ranking Analysis
  • Post-MBA Salary Trends
  • Post-MBA Job Function & Industry Analysis
  • Post-MBA City Review
  • MBA Application Essay Tips
  • School Specific Essay Tips
  • GMAT Preparation Tips
  • MBA Admission Interview Tips
  • School Specific Interview Tips
  • Funding Guidance and
  • Special Consultation Service (only for Subscribers)

Subscribe to F1GMAT's Newsletter