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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. 0^0
The angle intersecting the circumference is always the largest angle - and is always 90 degrees.
8
Undefined
2

2. x^2 = 9. What is the value of x?
The greatest value minus the smallest.
Triangles with same measure and same side lengths.
3 - -3
F(x) - c

3. Define an 'expression'.
Sqrt 12
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 = I (1 + rt)
9 : 25

4. If Madagascar'S exports totaled 1.3 billion in 2009 - and 4% came from China - what was the value in millions of the country'S exports to China?
4:9. The ratio of the areas of two similar triangles equals the square of the ratio of the corresponding sides.
52
F(x + c)
Circumference = Diameter(pi). Use pythagorean theorem to find the diagonal of the square (the diameter).

5. Can you subtract 3sqrt4 from sqrt4?
The two xes after factoring.
Yes - like radicals can be added/subtracted.
All numbers which can be expressed as a ratio of two integers. (All integers and fractions.) (-2 - 1 - .25 - 1/2)
2(pi)r^2 + 2(pi)rh

6. A number is divisible by 9 if...
1:sqrt3:2
N! / (k!)(n-k)!
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.
The sum of digits is divisible by 9.

7. If 8 schools are in a conference - how many games are played if each team plays each other exactly once?
IV
3/2 - 5/3
90 degrees
28. n = 8 - k = 2. n! / k!(n-k)!

8. 7/8 in percent?
A reflection about the origin.
48
87.5%
A grouping of the members within a set based on a shared characteristic.

9. What is the slope of a horizontal line?
3/2 - 5/3
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)
A set with no members - denoted by a circle with a diagonal through it.
0

10. What is the 'Solution' for a set of inequalities.
71 - 73 - 79
The longest arc between points A and B on a circle'S diameter.
The overlapping sections.
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

11. What is the ratio of the surface area of a cube with an edge of 10 to the surface area of a rectangular solid with dimensions 2 - 4 - and 6?
x^(4+7) = x^11
3 - -3
413.03 / 10^4 (move the decimal point 4 places to the left)
75:11

12. What is a tangent?
C = 2(pi)r
(a - b)(a + b)
A tangent is a line that only touches one point on the circumference of a circle.
Yes. [i.e. f(x) = x^2 - 1

13. Is 0 even or odd?
1/2 times 7/3
Even
A = I (1 + rt)
4:5

14. What is the coefficient of the x^2 term in the product of (x + 1)(x + 2)(x -1)?
18
4:5
Yes - because you can factor out a perfect square (36). Sqrt(36 x 2) = sqrt36 X sqrt2 = 6sqrt2.
2

15. 1/6 in percent?
F(x) - c
The sum of its digits is divisible by 3.
(a - b)^2
16.6666%

16. If you have a set of n objects - but you only want to order k of them - what formula do you use to determine the number of permutations?
Diameter(Pi)
6 : 1 : 2
When the function is not defined for all real numbers -; only a subset of the real numbers.
N! / (n-k)!

17. a^0 =
12! / 5!7! = 792
The graph of 3(x - 1)^2 is a translation (shift) of the graph one unit or space to the right.
4:9. The ratio of the areas of two similar triangles equals the square of the ratio of the corresponding sides.
1

18. What are the irrational numbers?

19. How to determine percent decrease?
1 & 37/132
All numbers which can be expressed as a ratio of two integers. (All integers and fractions.) (-2 - 1 - .25 - 1/2)
(amount of decrease/original price) x 100%
When we need to avoid having a zero in the denominator or avoid taking the square root of a number.

20. What is it called when a point is reflected to the quadrant opposite it (i.e. I to III or II to IV)?
500
A reflection about the origin.
F(x) + c
Undefined

21. What is the side length of an equilateral triangle with altitude 6?
71 - 73 - 79
Sqrt 12
Undefined - because we can'T divide by 0.
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...

22. What is the formula for compounded interest?
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.
F(x-c)
500
16^8 - 64^5 = (4^3)^5 = 4^15 - 16^8=(4^2)^8 = 4^16

23. x^(-y)=
1/(x^y)
A tangent is a line that only touches one point on the circumference of a circle.
The curve opens downward and the vertex is the maximum point on the graph.
A = pi(r^2)

24. 10<all primes<20
11 - 13 - 17 - 19
4725
F(x) + c
Lies opposite the greater angle

25. Length of an arc of a circle?
Angle/360 x 2(pi)r
Sqrt 12
2 & 3/7
Infinite.

26. To convert a decimal to a percent...
10! / (10-3)! = 720
From northeast - counterclockwise. I - II - III - IV
Sector area = (n/360) X (pi)r^2
...multiply by 100.

27. Simplify 9^(1/2) X 4^3 X 2^(-6)?
3
A 30-60-90 triangle.
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.
IV

28. What are the members or elements of a set?
Relationship cannot be determined (what if x is negative?)
When we need to avoid having a zero in the denominator or avoid taking the square root of a number.
The objects within a set.
Undefined - because we can'T divide by 0.

29. There are 10 finalists for the school spelling bee. A first - second - and third place trophy will be awarded. How many different people can get the three prizes?
2
10! / 3!(10-3)! = 120
3/2 - 5/3
The set of elements found in both A and B.

30. Evaluate 4/11 + 11/12
53 - 59
1 & 37/132
The longest arc between points A and B on a circle'S diameter.
(amount of decrease/original price) x 100%

31. Legs: 3 - 4. Hypotenuse?
5
Yes. [i.e. f(x) = x^2 - 1
1:sqrt3:2
1

32. What is an arc of a circle?
1/a^6
An arc is a portion of a circumference of a circle.
12! / 5!7! = 792
61 - 67

33. Convert 0.7% to a fraction.
83.333%
53 - 59
7 / 1000
10! / (10-3)! = 720

34. There are 10 finalists for the school spelling bee. A first - second - and third place trophy will be awarded. In how many ways can the judges award the 3 prizes?
No - only like radicals can be added.
52
The two xes after factoring.
10! / (10-3)! = 720

35. What is the ratio of the sides of an isosceles right triangle?
1:1:sqrt2
3
x^(2(4)) =x^8 = (x^4)^2
Undefined - because we can'T divide by 0.

36. Evaluate 3& 2/7 / 1/3
2 & 3/7
9 & 6/7
4:5
The shortest arc between points A and B on a circle'S diameter.

37. Which is greater? 200x^295 or 10x^294?
4096
Yes - because you can factor out a perfect square (36). Sqrt(36 x 2) = sqrt36 X sqrt2 = 6sqrt2.
x = [(-b)+/- (sqrt b^2 - 4ac)]/2a
Relationship cannot be determined (what if x is negative?)

38. Describe the relationship between 3x^2 and 3(x - 1)^2
441000 = 1 10 10 10 21 * 21
(a + b)^2
70
The graph of 3(x - 1)^2 is a translation (shift) of the graph one unit or space to the right.

39. Evaluate (4^3)^2
4096
12.5%
From northeast - counterclockwise. I - II - III - IV
180 degrees

40. 8.84 / 5.2
Members or elements
1.7
10
The objects within a set.

41. What is an exterior angle?
An angle which is supplementary to an interior angle.
67 - 71 - 73
C = 2(pi)r
52

42. For similar triangles - the ratio of their corresponding sides is 2:3. What is the ratio of their areas?
4:9. The ratio of the areas of two similar triangles equals the square of the ratio of the corresponding sides.
5 OR -5
Cd
The overlapping sections.

43. What is a chord of a circle?
The empty set - denoted by a circle with a diagonal through it.
A chord is a line segment joining two points on a circle.
Factors are few - multiples are many.
x^(2(4)) =x^8 = (x^4)^2

44. What is the order of operations?
PEMDAS (Parentheses Exponents Multiplication/Division Addition/Subtraction)
N! / (k!)(n-k)!
27^(-4)
(a - b)^2

45. A company places a 6-symbol code on each product. The code consists of the letter T - followed by 3 numerical digits - and then 2 consonants (Y is a conson). How many codes are possible?
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...
441000 = 1 10 10 10 21 * 21
61 - 67
The set of elements found in both A and B.

46. Which quadrant is the upper left hand?
The shortest arc between points A and B on a circle'S diameter.
II
1/2 times 7/3
The sum of its digits is divisible by 3.

47. What is the 'Range' of a series of numbers?
The greatest value minus the smallest.
2sqrt6
A set with a number of elements which can be counted.
3

48. In a regular polygon with n sides - the formula for the sum of interior angles
(n-2) x 180
Undefined - because we can'T divide by 0.
180 degrees
Circumference = Diameter(pi). Use pythagorean theorem to find the diagonal of the square (the diameter).

49. A brick with dimensions 10. 15 and 25 weighs 1.5 kg. A second brick (same density) has dimensions 12 - 18 - and 30. What is the weight of the second brick?
5
From northeast - counterclockwise. I - II - III - IV
2.592 kg
A set with no members - denoted by a circle with a diagonal through it.

50. What is the graph of f(x) shifted downward c units or spaces?
F(x) - c
2.592 kg
From northeast - counterclockwise. I - II - III - IV
... the square of the ratios of the corresponding sides.