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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. 20<all primes<30
23 - 29
F(x) - c
Divide by 100.
x = [(-b)+/- (sqrt b^2 - 4ac)]/2a

2. Factor a^2 + 2ab + b^2
(a + b)^2
C = 2(pi)r
Infinite.
$3 -500 in the 9% and $2 -500 in the 7%.

3. What is the sum of the angles of a triangle?
Relationship cannot be determined (what if x is negative?)
8
180 degrees
53 - 59

4. Evaluate 4/11 + 11/12
5 OR -5
The graph of 3(x - 1)^2 is a translation (shift) of the graph one unit or space to the right.
1 & 37/132
Undefined - because we can'T divide by 0.

5. a^2 - b^2 =
10! / 3!(10-3)! = 120
20.5
53 - 59
(a - b)(a + b)

6. What is the absolute value function?
The overlapping sections.
G(x) = {x}
1 & 37/132
3/2 - 5/3

7. x^2 = 9. What is the value of x?
Infinite.
From northeast - counterclockwise. I - II - III - IV
The third side is greater than the difference and less than the sum.
3 - -3

8. 5/6 in percent?
83.333%
Circumference = Diameter(pi). Use pythagorean theorem to find the diagonal of the square (the diameter).
23 - 29
The curve opens downward and the vertex is the maximum point on the graph.

9. To convert a decimal to a percent...
y = (x + 5)/2
3
The two xes after factoring.
...multiply by 100.

10. 1/2 divided by 3/7 is the same as
1/2 times 7/3
I
Angle/360 x (pi)r^2
0

11. What is the common monomial factor in the expression 4(c^3)d - (c^2)(d^2) + 2cd?
1/(x^y)
Cd
180 degrees
37.5%

12. 1/8 in percent?
(a + b)^2
From northeast - counterclockwise. I - II - III - IV
1
12.5%

13. Define an 'expression'.
x = [(-b)+/- (sqrt b^2 - 4ac)]/2a
(a - b)^2
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)
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)

14. What is a piecewise equation?
71 - 73 - 79
It is a function defined by more than one equation - where each equation applies to a different part of the domain of the function.
True
500

15. What is the graph of f(x) shifted left c units or spaces?
8
When the function is not defined for all real numbers -; only a subset of the real numbers.
F(x + c)
N! / (k!)(n-k)!

16. For what values should the domain be restricted for the function f(x) = sqrt(x + 8)
1
N! / (n-k)!
8
3 - -3

17. In a triangle where the two legs are 4 and 3 - what is the value of a line directly intersecting the middle coming from the meeting point of the two legs?
83.333%
(6 x 2)(sqrt3 x sqrt5) = 12sqrt15
2
2.4. We calculate the area (6) and then turn the triangle on its side and use x as the height to calculate again. (5x)/2=6

18. What is the intersection of A and B?
0
The set of elements found in both A and B.
C = 2(pi)r
61 - 67

19. 30< all primes<40
Two angles whose sum is 90.
2sqrt6
No - only like radicals can be added.
31 - 37

20. Pi is a ratio of what to what?

21. Can the output value of a function have more than one input value?
x^(4+7) = x^11
Yes. [i.e. f(x) = x^2 - 1
The steeper the slope.
All numbers multiples of 1.

22. What is the ratio of the sides of a 30-60-90 triangle?
1:sqrt3:2
2 & 3/7
11 - 13 - 17 - 19
The set of elements found in both A and B.

23. To multiply a number by 10^x
Move the decimal point to the right x places
Divide by 100.
3
180

24. How many digits are there between the decimal point and the first even digit in the decimal equivalent of 1/[(2^8)(5^3)]
The second graph is less steep.
1:sqrt3:2
0
6

25. If the 80th percentile of the measurements is 72degrees - about how many measurments are between 69 degrees and 72 degrees? Round your answer to the nearest tenth
Undefined
18
The interesection of A and B.
1 & 37/132

26. What is an exterior angle?
A set with no members - denoted by a circle with a diagonal through it.
An angle which is supplementary to an interior angle.
When we need to avoid having a zero in the denominator or avoid taking the square root of a number.
441000 = 1 10 10 10 21 * 21

27. What are complementary angles?
1
Two angles whose sum is 90.
$11 -448
0

28. What is the third quartile of the following data set: 44 - 58 - 63 - 63 - 68 - 70 - 82
70
Divide by 100.
4:5
The direction of the inequality is reversed.

29. a^2 - 2ab + b^2
(a - b)^2
37.5%
413.03 / 10^4 (move the decimal point 4 places to the left)
F(x + c)

30. Suppose that the graph of f(x) is the result of stretching y=x + 5 away from the x-axis by a factor of 2. What is the new equation for the graph f(x)?
A = I (1 + rt)
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)
(a + b)^2
y = (x + 5)/2

31. Circumference of a circle?
F(x + c)
10! / (10-3)! = 720
A set with no members - denoted by a circle with a diagonal through it.
Diameter(Pi)

32. Suppose you have a set of n objects - and you want to select k of them - but the order doesn'T matter. What formula do you use to determine the number of combinations of n objects taken k at a time?
2sqrt6
Angle/360 x 2(pi)r
N! / (k!)(n-k)!
Yes - because you can factor out a perfect square (36). Sqrt(36 x 2) = sqrt36 X sqrt2 = 6sqrt2.

33. What is it called when a point is reflected to the quadrant opposite it (i.e. I to III or II to IV)?
III
x^(6-3) = x^3
2(pi)r^2 + 2(pi)rh
A reflection about the origin.

34. What number between 70 & 75 - inclusive - has the greatest number of factors?
1 & 37/132
70
The longest arc between points A and B on a circle'S diameter.
72

35. sqrt 2(sqrt 6)=
6
Sqrt 12
0
23 - 29

36. How to find the diagonal of a rectangular solid?
The second graph is less steep.
Use Pythagorean theorem twice. (Once across the surface and then a is the diagonal of surface and b is an edge).
10! / (10-3)! = 720
4:9. The ratio of the areas of two similar triangles equals the square of the ratio of the corresponding sides.

37. What are 'Supplementary angles?'
0
Two angles whose sum is 180.
A subset.
The steeper the slope.

38. A cylinder has a surface area of 22pi. If the cylinder has a height of 10 - what is the radius?
16^8 - 64^5 = (4^3)^5 = 4^15 - 16^8=(4^2)^8 = 4^16
...multiply by 100.
1/2 times 7/3
1

39. 200 <_ x <_ 300. How many values of x are divisible by 5 & 8?
The angle intersecting the circumference is always the largest angle - and is always 90 degrees.
3
441000 = 1 10 10 10 21 * 21
The set of elements found in both A and B.

40. 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?
$3 -500 in the 9% and $2 -500 in the 7%.
1/2 times 7/3
The longest arc between points A and B on a circle'S diameter.
1

41. (6sqrt3) x (2sqrt5) =
6 : 1 : 2
(6 x 2)(sqrt3 x sqrt5) = 12sqrt15
[(7+ sqrt93) /2] - [(7 - sqrt93) / 2]
27^(-4)

42. How to find the circumference of a circle which circumscribes a square?
x= (1.2)(.8)lw
A reflection about the origin.
Circumference = Diameter(pi). Use pythagorean theorem to find the diagonal of the square (the diameter).
18

43. Simplify the expression (p^2 - q^2)/ -5(q - p)
III
(p + q)/5
(b + c)
G(x) = {x}

44. Order of quadrants:
From northeast - counterclockwise. I - II - III - IV
16.6666%
The two xes after factoring.
3 - -3

45. The objects in a set are called two names:
(a - b)(a + b)
Members or elements
1 & 37/132
1/2 times 7/3

46. What does scientific notation mean?
7 / 1000
10! / (10-3)! = 720
Expressing a number as the product of a decimal between 1 and 10 - and a power of 10.
5 OR -5

47. 10^6 has how many zeroes?
Two angles whose sum is 90.
12sqrt2
72
6

48. What are the smallest three prime numbers greater than 65?
67 - 71 - 73
90 degrees
71 - 73 - 79
PEMDAS (Parentheses Exponents Multiplication/Division Addition/Subtraction)

49. 50 < all primes< 60
N! / (n-k)!
130pi
Relationship cannot be determined (what if x is negative?)
53 - 59

50. The four angles around a point measure y - 2y - 35 and 55 respectively. What is the value of y?
A = I (1 + rt)
90
2(pi)r^2 + 2(pi)rh
(b + c)