Test your basic knowledge |

GRE Math Rules

Subjects : gre, math

Instructions:

Answer 50 questions in 15 minutes.
If you are not ready to take this test, you can study here.
Match each statement with the correct term.
Don't refresh. All questions and answers are randomly picked and ordered every time you load a test.

This is a study tool. The 3 wrong answers for each question are randomly chosen from answers to other questions. So, you might find at times the answers obvious, but you will see it re-enforces your understanding as you take the test each time.

1. what'S the median if there are an even number of data points?
(n-2)(180 degrees)
Mean of the two middle ones
Last three digits (taken together) are divisible by 8
2pi*r

2. volume of rectangle
P(E) + P(F) - P(E and F)
1/2(b1 + b2)h - where b1 and b2 are the two parallel sides
Lwh
P(E or F) = P(E) + P(F)

3. independence of two events E and F
x^(a+b)
P(E and F) = P(E)P(F)
Opposite angles formed by two intersecting lines; always congruent
1 if decimals - 100 if percents

4. (x^a)(x^b)
N!/(n-k)!
x^(a+b)
1/2 base * height
Invert the second fraction and multiply them

5. area of rectangle
1
Subtract the mean from each value and divide by the standard deviation
The sum of the areas of the six faces: 2(lw + lh + wh)
Number of outcomes yielding E / number of total outcomes

6. (x^a)^b
x^ab
x^(a+b)
Number of outcomes yielding E / number of total outcomes
Opposite angles formed by two intersecting lines; always congruent

7. (x^a)/(x^b)
Last two digits (taken together) are divisible by 4
x^(a-b) or a/x^(b-a)
Sum of its digits is divisible by 9
Three sides congruent - two sides and included angle - two angles and included side

8. area of cylinder
x^(a+b)
1/2(b1 + b2)h - where b1 and b2 are the two parallel sides
2(pir^2) + 2pirh; the two bases and the side
x^ab

9. similar triangles
Lwh
Invert the second fraction and multiply them
Last two digits (taken together) are divisible by 4
Congruent angles (check this to be sure) but possibly different size. Can use proportions to get other values by cross-multiplication

10. area of parallelogram
2pi*r
1/x^a
x^ab
Base * height

11. mutually exclusive
The sum of the areas of the six faces: 2(lw + lh + wh)
Last three digits (taken together) are divisible by 8
P(E or F) = P(E) + P(F)
Base * height

12. isosceles triangle
At least two congruent sides; the angles opposite these sides are also congruent
1 if decimals - 100 if percents
Rules for 2 and three: even and the sum of its digits is divisible by three
Pi * r^2

13. area of triangle
Congruent angles (check this to be sure) but possibly different size. Can use proportions to get other values by cross-multiplication
N-2
(1st digit + 3rd + 5th...) - (2nd + 4th + 6th...) is divisible by 11.
1/2 base * height

14. permutations of n different objects
Area of sector has the same proportion to the total area that the arc measure (angle) has to 360 degrees.
1/x^a
N-2
N(n-1)(n-2)...(2)(1) = n!

15. area of a non-right triangle
101010
x^ab
In computing the average squared difference from the mean (taking the root of this is the standard deviation) - divide by n-1 instead of n
Still bh/2 - but you can draw h as a line perpendicular to an extension of any side you take as the base.

16. union of sets A and B
Last three digits (taken together) are divisible by 8
A list is ordered and can have duplicates
A + B - their intersection
Last two digits (taken together) are divisible by 4

17. chord
Three sides congruent - two sides and included angle - two angles and included side
Any line connecting two points on a circle. The diameter is a chord
The sum of the areas of the six faces: 2(lw + lh + wh)
1/2 base * height

18. hypotenuse
The sum of the areas of the six faces: 2(lw + lh + wh)
N-2
Side opposite the right angle
(n-2)(180 degrees)

19. divisible by 3
1
Divide it by the prime numbers from 2 to the closest to the square root of the number (round down).
Sum of its digits is divisible by 3
All its interior angles are congruent

20. probability that either E or F occur
A list is ordered and can have duplicates
|S|
P(E) + P(F) - P(E and F)
(1st digit + 3rd + 5th...) - (2nd + 4th + 6th...) is divisible by 11.

21. area of trapezoid
Always equal - i.e. 9 choose 3 = 9 choose 6
Last two digits (taken together) are divisible by 4
1/2(b1 + b2)h - where b1 and b2 are the two parallel sides
Less affected by outliers than the mean

22. x^0
A list is ordered and can have duplicates
1/2(b1 + b2)h - where b1 and b2 are the two parallel sides
Three sides congruent - two sides and included angle - two angles and included side
1

23. area of sector of circle
Lwh
A list is ordered and can have duplicates
Sum of its digits is divisible by 3
Area of sector has the same proportion to the total area that the arc measure (angle) has to 360 degrees.

24. how many triangles can a polygon of n sides be divided into?
x^(a-b) or a/x^(b-a)
N-2
Side opposite the right angle
Sum of its digits is divisible by 3

25. length of arc of circle
Three sides congruent - two sides and included angle - two angles and included side
Length of arc has the same proportion to the circumference that the arc measure (angle) has to 360 degrees.
P(E or F) = P(E) + P(F)
1 - 1 - root(2)

26. vertical angles
Opposite angles formed by two intersecting lines; always congruent
Base * height
101010
Pi*r^2h

27. number of elements in set S
(n-2)(180 degrees)
P(E and F) = P(E)P(F)
|S|
Length of arc has the same proportion to the circumference that the arc measure (angle) has to 360 degrees.

28. sum of relative frequencies in a frequency distribution
Pi*r^2h
1 if decimals - 100 if percents
A list is ordered and can have duplicates
Number of outcomes yielding E / number of total outcomes

29. permutations of n objects taken k at a time (order counts)
Sum of its digits is divisible by 9
N!/(n-k)!
Sum of its digits is divisible by 3
P(E) + P(F) - P(E and F)

30. divisible by 8
Last three digits (taken together) are divisible by 8
x^(a+b)
1 - 2 - root(3); note that this is half of an equilateral triangle
Pi*r^2h

31. probability of an event E
Number of outcomes yielding E / number of total outcomes
N!/(n-k)!
|S|
1

32. divisible by 4
Last two digits (taken together) are divisible by 4
2pi*r
Congruent angles (check this to be sure) but possibly different size. Can use proportions to get other values by cross-multiplication
Area of sector has the same proportion to the total area that the arc measure (angle) has to 360 degrees.

33. regular polygon
(1st digit + 3rd + 5th...) - (2nd + 4th + 6th...) is divisible by 11.
1/x^a
All its interior angles are congruent
1098 etc

34. (x^a)(y^a)
1
Base * height
A list is ordered and can have duplicates
(xy)^a

35. (x/y)^a
(x^a)/(y^a)
Any line connecting two points on a circle. The diameter is a chord
1
All its interior angles are congruent

36. congruency of triangles
N-2
Three sides congruent - two sides and included angle - two angles and included side
P(E or F) = P(E) + P(F)
x^ab

37. dividing fractions
All its interior angles are congruent
Divide it by the prime numbers from 2 to the closest to the square root of the number (round down).
x^(a-b) or a/x^(b-a)
Invert the second fraction and multiply them

38. differences between a set and a list
101010
P(E) + P(F) - P(E and F)
At least two congruent sides; the angles opposite these sides are also congruent
A list is ordered and can have duplicates

39. divisible by 6
Side opposite the right angle
Rules for 2 and three: even and the sum of its digits is divisible by three
N!/(n-k)!
At least two congruent sides; the angles opposite these sides are also congruent

40. area of circle
At least two congruent sides; the angles opposite these sides are also congruent
Pi * r^2
x^ab
P(E) + P(F) - P(E and F)

41. possible combinations of three digits allowing repeats
x^(a+b)
1/2(b1 + b2)h - where b1 and b2 are the two parallel sides
101010
P(E and F) = P(E)P(F)

42. how to tell if something is prime
At least two congruent sides; the angles opposite these sides are also congruent
|S|
1098 etc
Divide it by the prime numbers from 2 to the closest to the square root of the number (round down).

43. divisible by 9
1/2 base * height
Less affected by outliers than the mean
Last two digits (taken together) are divisible by 4
Sum of its digits is divisible by 9

44. advantage of median
x^(a-b) or a/x^(b-a)
Less affected by outliers than the mean
At least two congruent sides; the angles opposite these sides are also congruent
Congruent angles (check this to be sure) but possibly different size. Can use proportions to get other values by cross-multiplication

45. x^-a
In computing the average squared difference from the mean (taking the root of this is the standard deviation) - divide by n-1 instead of n
1/x^a
Invert the second fraction and multiply them
2(pir^2) + 2pirh; the two bases and the side

46. sides of 30/60/90 triangle
All its interior angles are congruent
x^ab
Side opposite the right angle
1 - 2 - root(3); note that this is half of an equilateral triangle

47. difference between normal or population standard deviation and the sample standard deviation
In computing the average squared difference from the mean (taking the root of this is the standard deviation) - divide by n-1 instead of n
Pi * r^2
Area of sector has the same proportion to the total area that the arc measure (angle) has to 360 degrees.
(xy)^a

48. possible combinations of three digits without allowing repeats
101010
Opposite angles formed by two intersecting lines; always congruent
1098 etc
Any line connecting two points on a circle. The diameter is a chord

49. volume of cylinder
Pi*r^2h
In computing the average squared difference from the mean (taking the root of this is the standard deviation) - divide by n-1 instead of n
Opposite angles formed by two intersecting lines; always congruent
Rules for 2 and three: even and the sum of its digits is divisible by three

50. combinations of n objects taken k at a time (order doesn'T count)
Base * height
Sum of its digits is divisible by 3
N!/k!(n-k)! which is also denotes as n choose k
Congruent angles (check this to be sure) but possibly different size. Can use proportions to get other values by cross-multiplication