General Math Strategies Flashcards Preview

GRE Math Review > General Math Strategies > Flashcards

Flashcards in General Math Strategies Deck (14)
Loading flashcards...
1

How to square a number ending in 5

1. Remove 5 from digits
2. Add 1 to the remaining digit/s
3. N • (N+1) = ?
4. Add 25 after finding product above

2

Why not use calculator

1. Slow
2. Simplify through logic by estimation needed more than precise calculation

3

Estimate: "What is 26.3% of $7,935?

1. Round 26.3% to 25%, which is also ¼
2. Round 7935 to 8000
3. A fourth of 8000 is 2000
4. So pick an answer closest to 2000

4

When dividing large number by 5...

Double N, then divide by 10, or vise-versa, whichever is easier

5

What logic of dividing-by-five suggest

The related logic of doubling and halving

6

Apply doubling-and-halving trick to: 16 * 35 = N

1. Half 16 so that it is reduced to 8
2. Double 35 so that it becomes 70
3. 8 * 7 = 56
4. Add 0 after 56
5. 560

7

When to use doubling-and-halving

When multiplying two large numbers

8

Essence of QC questions

Comparing two quantities to see which is bigger

9

What are the four standard choices for every Quantitative Comparison GRE math questions?

1. Quantity A is greater
2. Quantity B is greater
3. The two quantities are equal
4. The relationship cannot be determined from the information given

10

What fourth standard QC answer choice mean

That variables within specified ranges allow for different results

11

3 essential QC facts

1. Answers evenly distributed between four standard choices
2. 7-9 QC questions
3. Easy ones take than 45 sec to answer; harder ones less than 2 min

12

Best QC trick

Calculate only to APPROXIMATE answer

13

2 QC tricks to remember

1. Part-wise
2. Rounding

14

QC matching operations trick to simplify problem

1. + same # to both quantities
2. - same # from both quantities
3. * or / both quantities by same positive #