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GRE Math: Common Errors

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 is a set with no members called?
130pi
The empty set - denoted by a circle with a diagonal through it.
No - only like radicals can be added.
(a - b)(a + b)

2. A number is divisible by 4 is...
A central angle is an angle formed by 2 radii.
No - only like radicals can be added.
(a - b)(a + b)
Its last two digits are divisible by 4.

3. To convert a percent to a fraction....
x(x - y + 1)
An algebraic expression is a combination of one of more terms. Terms in an expression are separated by either addition or subtraction signs. (3xy - 4ab - -5cd - x^2 + x - 1)
Divide by 100.
1.0843 X 10^11

4. Define a 'Term' -
A term is a numerical constant or the product (or quotient) of a numerical constant and one or more variables. (3x - 4x^2 and 2a/c)
$3 -500 in the 9% and $2 -500 in the 7%.
130pi
F(x) - c

5. Formula to calculate arc length?
Arc length = (n/360) x pi(2r) where n is the number of degrees.
1
Diameter(Pi)
31 - 37

6. 1/6 in percent?
[(7+ sqrt93) /2] - [(7 - sqrt93) / 2]
The second graph is less steep.
16.6666%
The objects within a set.

7. Legs: 3 - 4. Hypotenuse?
41 - 43 - 47
A circle centered at -2 - -2 with radius 3.
x^(2(4)) =x^8 = (x^4)^2
5

8. Can the input value of a function have more than one output value (i.e. x: y - y1)?
No - the input value has exactly one output.
Relationship cannot be determined (what if x is negative?)
The curve opens upward and the vertex is the minimal point on the graph.
The greatest value minus the smallest.

9. Factor x^2 - xy + x.
6 : 1 : 2
28. n = 8 - k = 2. n! / k!(n-k)!
x(x - y + 1)
The union of A and B.

10. a^2 + 2ab + b^2
13pi / 2
(a + b)^2
83.333%
72

11. What is the coefficient of the x^2 term in the product of (x + 1)(x + 2)(x -1)?
Use Pythagorean theorem twice. (Once across the surface and then a is the diagonal of surface and b is an edge).
Undefined - because we can'T divide by 0.
Its divisible by 2 and by 3.
2

12. In a triangle inscribed inside a circle - where the diameter is one side of the triangle - which angle is largest?
The angle intersecting the circumference is always the largest angle - and is always 90 degrees.
The curve opens upward and the vertex is the minimal point on the graph.
Two angles whose sum is 180.
Two equal sides and two equal angles.

13. In a regular polygon with n sides - the formula for the sum of interior angles
IV
(n-2) x 180
G(x) = {x}
31 - 37

14. When the 'a' in a parabola is positive....
75:11
13
The curve opens upward and the vertex is the minimal point on the graph.
72

15. Factor a^2 + 2ab + b^2
1
(a + b)^2
III
83.333%

16. x^4 + x^7 =
Pi is the ratio of a circle'S circumference to its diameter.
The second graph is less steep.
x^(4+7) = x^11
54sqrt3. (divide the hexagon into 6 congruent equilateral triangles.

17. If 10800 is invested at a simple interest rate of 4% - what is the value of the investment after 18 months?
71 - 73 - 79
The two xes after factoring.
$11 -448
Cd

18. What is the ratio of the sides of a 30-60-90 triangle?
1:sqrt3:2
90 degrees
Infinite.
Cd

19. 30< all primes<40
Even
1:sqrt3:2
31 - 37
10! / 3!(10-3)! = 120

20. The perimeter of a square is 48 inches. The length of its diagonal is:
(p + q)/5
12sqrt2
4725
x= (1.2)(.8)lw

21. (a^-1)/a^5
9 : 25
67 - 71 - 73
1/a^6
130pi

22. The ratio of the areas of two similar polygons is ...
... the square of the ratios of the corresponding sides.
x^(6-3) = x^3
An angle which is supplementary to an interior angle.
9 : 25

23. What is the 'Range' of a series of numbers?
180
Use Pythagorean theorem twice. (Once across the surface and then a is the diagonal of surface and b is an edge).
All numbers which can be expressed as a ratio of two integers. (All integers and fractions.) (-2 - 1 - .25 - 1/2)
The greatest value minus the smallest.

24. What does the graph x^2 + y^2 = 64 look like?
A circle centered on the origin with radius 8.
x^(2(4)) =x^8 = (x^4)^2
The direction of the inequality is reversed.
x^(6-3) = x^3

25. What is the area of a regular hexagon with side 6?
The direction of the inequality is reversed.
Ax^2 + bx + c where a -b and c are constants and a /=0
54sqrt3. (divide the hexagon into 6 congruent equilateral triangles.
71 - 73 - 79

26. What is the order of operations?
Angle/360 x 2(pi)r
A grouping of the members within a set based on a shared characteristic.
PEMDAS (Parentheses Exponents Multiplication/Division Addition/Subtraction)
IV

27. What is the graph of f(x) shifted downward c units or spaces?
An arc is a portion of a circumference of a circle.
180 degrees
52
F(x) - c

28. What is the formula for compounded interest?
90pi
Arc length = (n/360) x pi(2r) where n is the number of degrees.
A= I (1 + (r/c))^tC - where I is the investment - C is the number of times compounded annually - and t is the number of years.
G(x) = {x}

29. What is the graph of f(x) shifted upward c units or spaces?
The longest arc between points A and B on a circle'S diameter.
9 : 25
3sqrt4
F(x) + c

30. A number is divisible by 3 if ...
The sum of its digits is divisible by 3.
6
10! / 3!(10-3)! = 120
6

31. What are the roots of the quadrinomial x^2 + 2x + 1?
A 30-60-90 triangle.
The two xes after factoring.
(b + c)
11 - 13 - 17 - 19

32. a^2 - b^2 =
(a - b)(a + b)
37.5%
Infinite.
1/2 times 7/3

33. What is a central angle?
1:sqrt3:2
90
A central angle is an angle formed by 2 radii.
The sum of digits is divisible by 9.

34. x^(-y)=
Angle/360 x 2(pi)r
[(7+ sqrt93) /2] - [(7 - sqrt93) / 2]
1/(x^y)
72

35. For similar triangles - the ratio of their corresponding sides is 2:3. What is the ratio of their areas?
4725
I
4:9. The ratio of the areas of two similar triangles equals the square of the ratio of the corresponding sides.
Yes. [i.e. f(x) = x^2 - 1

36. sqrt 2(sqrt 6)=
Members or elements
(base*height) / 2
Sqrt 12
2^9 / 2 = 256

37. The four angles around a point measure y - 2y - 35 and 55 respectively. What is the value of y?
True
No - only like radicals can be added.
90
Two equal sides and two equal angles.

38. Which quadrant is the lower left hand?
III
.0004809 X 10^11
A reflection about the origin.
A central angle is an angle formed by 2 radii.

39. How to determine percent decrease?
31 - 37
(amount of decrease/original price) x 100%
The steeper the slope.
130pi

40. 10^6 has how many zeroes?
Factors are few - multiples are many.
An arc is a portion of a circumference of a circle.
6
90pi

41. What is the set of elements which can be found in either A or B?
37.5%
The union of A and B.
All the numbers on the number line (negative - rational - irrational - decimal - integer). All the numbers on the GRE are real. (-2 - 1 - .25 - 1/2 - pi)
Pi is the ratio of a circle'S circumference to its diameter.

42. 413.03 x 10^(-4) =
Ax^2 + bx + c where a -b and c are constants and a /=0
2
All numbers which can be expressed as a ratio of two integers. (All integers and fractions.) (-2 - 1 - .25 - 1/2)
413.03 / 10^4 (move the decimal point 4 places to the left)

43. Area of a triangle?
Sector area = (n/360) X (pi)r^2
(base*height) / 2
The interesection of A and B.
$3 -500 in the 9% and $2 -500 in the 7%.

44. Can you subtract 3sqrt4 from sqrt4?
Yes - like radicals can be added/subtracted.
180
F(x) + c
A reflection about the axis.

45. 1:1:sqrt2 is the ratio of the sides of what kind of triangle?
5 OR -5
An isosceles right triangle.
1.0843 X 10^11
Factors are few - multiples are many.

46. How many digits are there between the decimal point and the first even digit in the decimal equivalent of 1/[(2^8)(5^3)]
0
x^(2(4)) =x^8 = (x^4)^2
(12/2) x (sqrt15 / sqrt5) = 6sqrt3
11 - 13 - 17 - 19

47. What is an exterior angle?
An angle which is supplementary to an interior angle.
Ax^2 + bx + c where a -b and c are constants and a /=0
Relationship cannot be determined (what if x is negative?)
II

48. (-1)^2 =
1
71 - 73 - 79
90 degrees
The set of output values for a function.

49. What is the graph of f(x) shifted left c units or spaces?
All real numbers which can'T be expressed as a ratio of two integers - positive and negative (pi - -sqrt3)
The overlapping sections.
...multiply by 100.
F(x + c)

50. 10<all primes<20
True
11 - 13 - 17 - 19
An angle which is supplementary to an interior angle.
83.333%