GRE math

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1. the angles in a triangle sum up to
180 degrees
2. order of operations
• parentheses first (innermost to outer)
• multiplication and division
3. percent formula
part= percent x whole
4. percent increase
percent increase= amount of increase/ original whole x 100%
5. percent decrease
percent decrease= amount of decrease/original whole x 100%
6. how to recognize if multiples of 2
last digit is even
7. how to recognize if multiples of 3
sum of digits is a multiple of 3
8. how to recognize multiples of 4
last two digits are multiples of 4
9. how to recognize multiples of 5
last digit is 5 or 0
10. how to recognize mulitples of 6
sum of digits is a multiple of 3 and last digit is even
11. how to recognize multiples of 9
sum of digits is a multiple of 9
12. how to recognize multiples of 10
last digit is 0
13. how to recognize multiples of 12
• sum of digits is a multiple of 3 and last two digits are a multiple of 4
14. average
average= sum of terms/ number of terms
15. using average to find sum
sum=(average) x (number of terms)
16. how to find the number of integers from A to B inclusive
B-A+1
17. median
put the numbers in numerical order and take to the middle number
18. mode
take the number that appears most often
19. range
take the positive difference between the greatest and least values
20. probability
probability= number of favorable outcomes/ total number of possible outcomes
21. polynomial
an expression consisting of the sum of two or more terms
22. inequalities
remember to reverse the inequality sign if you multiply or divide by a negative quality
23. absolute value
the distance the number is from zero to the number on the number line, absolute value is always positive
24. area of a triangle
are= 1/2 (base)(height)
25. isosceles triangles
two equal sides and two equal angles
26. equilateral triangles
three equal sides and three 60 degree angles
27. similar triangles
corresponding angles are equal and corresponding sides are proportional
28. how to find the hypotenuse or leg of a right triangle
• pythagorean theorum
• a2+ b2= c2
29. special right triangles
• 3:4:5
• 5:12:13
• 30 degree: 60 degree: 90 degree
• 45degree: 45 degree: 90 degree
• 1: √3: 2
• 1:1:√2
30. perimeter of rectangle
perimeter= 2(length + width)
31. area of rectangle
area= (length)(width)
32. area of square
area= side2
33. area of parallelogram
area= (base)(height)
34. area of trapezoid
break figure into rectangle and triangle
35. circumference of a circle
circumference= 2(pie)r= (pie)d
36. area of circle
area= (pie)r2
37. slope of line
slope= rise/run= change in y/change in x
38. simple interest problem
interest= (principal) x (interest rate)x time

• interest rate is expressed as decimal
• time is in years or fraction of years
39. finding compound interest
(final balance)= (principal) x (1+ interest rate/C)(time x C)

c= number of times compounded annually
40. find average rate
average A per B= Total A/Total B
41. average speed
average speed= total distance/ time
42. combined work problem
1/r + 1/s= 1/t

• r and s are number of hours it would take two people to complete work
• t is the total time
 Author: cfalgo1 ID: 224298 Card Set: GRE math Updated: 2013-06-20 20:50:59 Tags: GRE math Folders: Description: GRE math Show Answers: