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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. How to find the diagonal of a rectangular solid?
Yes. [i.e. f(x) = x^2 - 1
Use Pythagorean theorem twice. (Once across the surface and then a is the diagonal of surface and b is an edge).
6
The point of intersection of the systems.

2. 8.84 / 5.2
The steeper the slope.
0
48
1.7

3. How to find the area of a sector?
II
3 - -3
Angle/360 x (pi)r^2
75:11

4. In a triangle inscribed inside a circle - where the diameter is one side of the triangle - which angle is largest?
A 30-60-90 triangle.
The angle intersecting the circumference is always the largest angle - and is always 90 degrees.
An isosceles right triangle.
90

5. What is an exterior angle?
An expression with just one term (-6x - 2a^2)
An angle which is supplementary to an interior angle.
2.592 kg
Angle/360 x 2(pi)r

6. What is a central angle?
(base*height) / 2
A central angle is an angle formed by 2 radii.
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)
4.25 - 6 - 22

7. 1/2 divided by 3/7 is the same as
1/2 times 7/3
A = I (1 + rt)
(a - b)(a + b)
1/a^6

8. Hector invested $6000. Part was invested in account with 9% simple annual interest - and the rest in account with 7% simple annual interest. If he earned $490 in the first year of these investments - how much did he invest in each account?
31 - 37
Its last two digits are divisible by 4.
$3 -500 in the 9% and $2 -500 in the 7%.
Yes. [i.e. f(x) = x^2 - 1

9. x^6 / x^3
Part = Percent X Whole
x^(6-3) = x^3
x^(4+7) = x^11
A reflection about the origin.

10. 40 < all primes<50
All real numbers which can'T be expressed as a ratio of two integers - positive and negative (pi - -sqrt3)
41 - 43 - 47
20.5
An arc is a portion of a circumference of a circle.

11. 0^0
Sector area = (n/360) X (pi)r^2
When we need to avoid having a zero in the denominator or avoid taking the square root of a number.
A set with no members - denoted by a circle with a diagonal through it.
Undefined

12. 413.03 x 10^(-4) =
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)
413.03 / 10^4 (move the decimal point 4 places to the left)
An angle which is supplementary to an interior angle.
A = I (1 + rt)

13. 7/8 in percent?
6 : 1 : 2
87.5%
Triangles with same measure and same side lengths.
F(x) - c

14. What are the integers?
2
4:9. The ratio of the areas of two similar triangles equals the square of the ratio of the corresponding sides.
All numbers multiples of 1.
20.5

15. What are the roots of the quadrinomial x^2 + 2x + 1?
The two xes after factoring.
31 - 37
Its divisible by 2 and by 3.
Undefined

16. What is the 'Range' of a series of numbers?
(base*height) / 2
The greatest value minus the smallest.
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.
1

17. A number is divisible by 3 if ...
Use Pythagorean theorem twice. (Once across the surface and then a is the diagonal of surface and b is an edge).
2.592 kg
The sum of its digits is divisible by 3.
All numbers multiples of 1.

18. (12sqrt15) / (2sqrt5) =
Its negative reciprocal. (-b/a)
1
Infinite.
(12/2) x (sqrt15 / sqrt5) = 6sqrt3

19. What is the graph of f(x) shifted downward c units or spaces?
12sqrt2
1
Area of the base X height = (pi)hr^2
F(x) - c

20. Evaluate and write as a mixed number: 2/7 - 3/21 + 2 & 4/14
2 & 3/7
87.5%
Triangles with same measure and same side lengths.
90 degrees

21. What is a piecewise equation?
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)
x= (1.2)(.8)lw
It is a function defined by more than one equation - where each equation applies to a different part of the domain of the function.
The curve opens downward and the vertex is the maximum point on the graph.

22. What is the percent formula?
67 - 71 - 73
5 OR -5
... the square of the ratios of the corresponding sides.
Part = Percent X Whole

23. When the 'a' in a parabola is positive....
10! / (10-3)! = 720
9 : 25
The curve opens upward and the vertex is the minimal point on the graph.
54sqrt3. (divide the hexagon into 6 congruent equilateral triangles.

24. What is the slope of a horizontal line?
A set with a number of elements which can be counted.
y = (x + 5)/2
20.5
0

25. What is the area of a regular hexagon with side 6?
1
C = 2(pi)r
54sqrt3. (divide the hexagon into 6 congruent equilateral triangles.
2^9 / 2 = 256

26. Number of degrees in a triangle
180
Relationship cannot be determined (what if x is negative?)
... the square of the ratios of the corresponding sides.
A chord is a line segment joining two points on a circle.

27. Whats the difference between factors and multiples?
1
Factors are few - multiples are many.
The set of elements which can be found in either A or B.
$3 -500 in the 9% and $2 -500 in the 7%.

28. 3/8 in percent?
1:sqrt3:2
37.5%
A reflection about the axis.
An infinite set.

29. 20<all primes<30
The third side is greater than the difference and less than the sum.
23 - 29
The curve opens downward and the vertex is the maximum point on the graph.
Angle/360 x (pi)r^2

30. Define a 'monomial'
$3 -500 in the 9% and $2 -500 in the 7%.
The sum of its digits is divisible by 3.
The interesection of A and B.
An expression with just one term (-6x - 2a^2)

31. Convert 0.7% to a fraction.
9 : 25
7 / 1000
Yes - like radicals can be added/subtracted.
Its negative reciprocal. (-b/a)

32. A number is divisible by 9 if...
1/(x^y)
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.
Arc length = (n/360) x pi(2r) where n is the number of degrees.
The sum of digits is divisible by 9.

33. What is it called when a point is reflected to the quadrant opposite it (i.e. I to III or II to IV)?
A reflection about the origin.
The second graph is less steep.
72
3 - -3

34. What are the members or elements of a set?
71 - 73 - 79
4.25 - 6 - 22
1/2 times 7/3
The objects within a set.

35. What is a subset?
C = (pi)d
A grouping of the members within a set based on a shared characteristic.
130pi
52

36. Solve the quadratic equation ax^2 + bx + c= 0
x = [(-b)+/- (sqrt b^2 - 4ac)]/2a
4sqrt3. The triangle can be divided into two equal 30-60-90 triangles with side 6 as the side in which 6 = xsqrt3. So x =2sqrt3...
The set of elements which can be found in either A or B.
The empty set - denoted by a circle with a diagonal through it.

37. The ratio of the areas of two similar polygons is ...
4096
... the square of the ratios of the corresponding sides.
The shortest arc between points A and B on a circle'S diameter.
20.5

38. Write 10 -843 X 10^7 in scientific notation
Members or elements
1.0843 X 10^11
C = 2(pi)r
The two xes after factoring.

39. What is the intersection of A and B?
0
90
The set of elements found in both A and B.
A central angle is an angle formed by 2 radii.

40. What is an isoceles triangle?
Two equal sides and two equal angles.
The angle intersecting the circumference is always the largest angle - and is always 90 degrees.
1
27^(-4)

41. Legs 5 - 12. Hypotenuse?
500
13
70
3/2 - 5/3

42. Surface area for a cylinder?
C = 2(pi)r
A circle centered on the origin with radius 8.
53 - 59
2(pi)r^2 + 2(pi)rh

43. What does the graph (x+2)^2 + (y+2)^2 = 9 look like?
10! / (10-3)! = 720
90pi
A circle centered at -2 - -2 with radius 3.
Expressing a number as the product of a decimal between 1 and 10 - and a power of 10.

44. Simplify the expression (p^2 - q^2)/ -5(q - p)
(p + q)/5
13
5 OR -5
A set with no members - denoted by a circle with a diagonal through it.

45. 60 < all primes <70
5
It is a function defined by more than one equation - where each equation applies to a different part of the domain of the function.
3sqrt4
61 - 67

46. 1:1:sqrt2 is the ratio of the sides of what kind of triangle?
Angle/360 x 2(pi)r
An isosceles right triangle.
61 - 67
The empty set - denoted by a circle with a diagonal through it.

47. When does a function automatically have a restricted domain (2)?
53 - 59
55%
The greatest value minus the smallest.
When we need to avoid having a zero in the denominator or avoid taking the square root of a number.

48. What is a chord of a circle?
90 degrees
No - only like radicals can be added.
A chord is a line segment joining two points on a circle.
Ax^2 + bx + c where a -b and c are constants and a /=0

49. What is the third quartile of the following data set: 44 - 58 - 63 - 63 - 68 - 70 - 82
The curve opens upward and the vertex is the minimal point on the graph.
0
70
N! / (k!)(n-k)!

50. Suppose that the graph of f(x) is the result of sliding the graph of y=2x^2 down 3 units of spaces. What is the new equation?
I
A reflection about the axis.
y = 2x^2 - 3
An angle which is supplementary to an interior angle.