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GMAT Quick Math And Formulas

Subjects : gmat, 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. Simplifying a root
You cannot simplify this one
GMAT very often tries to trick you by giving a root linked by addition where it is tempting to simplify the terms - for example: √(25 + 16). It is tempting to think that this will result into 5 + 4 - but you can only simplify roots when the terms ins
1024
16.66%

2. 3^3
27
(a-b)(a^2+ab+b^2)
3125
2.23

3. 13^2
64
169
...yields a negative result (-1)^57 = -1
√25.16 = √25 . √16 = 5.4 - √50 . √18 = √50.18 = √900 = 30 - √144:16 = √144 : √16 = 12/4 = 3

4. √ 169
13
125
225
A^2 + 2ab + b^2

5. 1/20
You cannot simplify this one
5%
87.50%
{2 -3 -5 -7 -11 -13 -17 -19 -23 -29 -31 -37 -41 -43 -47 -53 -59 -61 -67 -71 -73 -79 -83 -89 -97}

6. 4^5
= the square root of 9 = 3
1024
2.449
8

7. 1/6
(A+B)(A-B)
16.66%
12.50%
81

8. a negative number raised to an even power...
83.33%
...yields a positive result (-1)^2 = 1
13
16

9. Multiples of 15
7776
256
15 - 30 - 45 - 60 - 75 - 90 - 105 - 120
3125

10. Prime Numbers between 1 - 100 (total of 25)
{2 -3 -5 -7 -11 -13 -17 -19 -23 -29 -31 -37 -41 -43 -47 -53 -59 -61 -67 -71 -73 -79 -83 -89 -97}
20%
169
128

11. Express 9^1/2 as a radical
12.50%
2
{2 -3 -5 -7 -11 -13 -17 -19 -23 -29 -31 -37 -41 -43 -47 -53 -59 -61 -67 -71 -73 -79 -83 -89 -97}
= the square root of 9 = 3

12. 11^2
256
121
27
83.33%

13. 1/2
196
83.33%
81
50%

14. √ 5
2.23
16.66%
(A+B)(A-B)
16

15. √ 625
8
(a+b)(a^2-ab+b^2)
121
25

16. 2^7
1024
128
2.449
25

17. Multiples of 8
5%
8 - 16 - 24 - 32 - 40 - 48 - 56 - 64 - 72 - 80 - 88 - 96 - 104 - 112 - 120
3125
7776

18. 3^4
81
196
(a+b)(a^2-ab+b^2)
A^2 + 2ab + b^2

19. 5^5
87.50%
Take the reciprocal of the base and change the sign of the exponent (2)^-2 = 1^2/2^2 = 1/4
3125
16.66%

20. to divide powers with the same base...
Subtract the exponents and keep the base the same 4^5/4^2 = 4^3
512
5%
625

21. 6^3
216
{2 -3 -5 -7 -11 -13 -17 -19 -23 -29 -31 -37 -41 -43 -47 -53 -59 -61 -67 -71 -73 -79 -83 -89 -97}
64
Multiply the exponents 7^2(^3) = 7^6

22. 7/8
16.67%
87.50%
81
243

23. Multiples of 12
20%
1.73
12 - 24 - 36 - 48 - 60 - 72 - 84 - 96 - 108 - 120
8

24. (a+b)^2 =
A^2 + 2ab + b^2
125
8.33%
GMAT very often tries to trick you by giving a root linked by addition where it is tempting to simplify the terms - for example: √(25 + 16). It is tempting to think that this will result into 5 + 4 - but you can only simplify roots when the terms ins

25. √ 3
32
512
2.449
1.73

26. 17^2
289
= the square root of 9 = 3
GMAT very often tries to trick you by giving a root linked by addition where it is tempting to simplify the terms - for example: √(25 + 16). It is tempting to think that this will result into 5 + 4 - but you can only simplify roots when the terms ins
128

27. raising a fraction between zero and 1 to a power...
8 - 16 - 24 - 32 - 40 - 48 - 56 - 64 - 72 - 80 - 88 - 96 - 104 - 112 - 120
...yields a smaller result (1/2)^2 = 1/4
40%
324

28. √ 2
(a-b)(a^2+ab+b^2)
128
1.41
3125

29. 15^2
225
Subtract the exponents and keep the base the same 4^5/4^2 = 4^3
5%
1024

30. 4^4
2.449
256
32
7776

31. 2^3
40%
8
Subtract the exponents and keep the base the same 4^5/4^2 = 4^3
87.50%

32. a negative number raised to an odd power...
25%
256
512
...yields a negative result (-1)^57 = -1

33. A^2-B^2
(A+B)(A-B)
√25.16 = √25 . √16 = 5.4 - √50 . √18 = √50.18 = √900 = 30 - √144:16 = √144 : √16 = 12/4 = 3
8.33%
87.50%

34. 2^8
8 - 16 - 24 - 32 - 40 - 48 - 56 - 64 - 72 - 80 - 88 - 96 - 104 - 112 - 120
64
256
A^2 + 2ab + b^2

35. 3^5
A^2 - 2ab + b^2
256
40%
243

36. Examples of roots simplification
√25.16 = √25 . √16 = 5.4 - √50 . √18 = √50.18 = √900 = 30 - √144:16 = √144 : √16 = 12/4 = 3
16.67%
32
...yields a smaller result (1/2)^2 = 1/4

37. 2^2
3125
12 - 24 - 36 - 48 - 60 - 72 - 84 - 96 - 108 - 120
256
4

38. to multiple powers (or raise a power to a power)
16.67%
Multiply the exponents 7^2(^3) = 7^6
(A+B)(A-B)
169

39. 2^5
1024
2.23
256
32

40. 2^6
81
√25.16 = √25 . √16 = 5.4 - √50 . √18 = √50.18 = √900 = 30 - √144:16 = √144 : √16 = 12/4 = 3
25
64

41. a^3-b^3
2
75%
(a-b)(a^2+ab+b^2)
A^2 + 2ab + b^2

42. 6^5
2.23
7776
8 - 16 - 24 - 32 - 40 - 48 - 56 - 64 - 72 - 80 - 88 - 96 - 104 - 112 - 120
1296

43. Express 8^1/3 as a radical
A^2 + 2ab + b^2
= the cube root of 8 = 2
256
125

44. 1/12
12 - 24 - 36 - 48 - 60 - 72 - 84 - 96 - 108 - 120
8.33%
256
...yields a smaller result (1/2)^2 = 1/4

45. 5/6
1024
12 - 24 - 36 - 48 - 60 - 72 - 84 - 96 - 108 - 120
83.33%
1024

46. what happens when an exponent is negative?
625
25
Take the reciprocal of the base and change the sign of the exponent (2)^-2 = 1^2/2^2 = 1/4
16

47. √ 4
243
2
1.41
361

48. to multiple powers with the same base...
Multiply the exponents 7^2(^3) = 7^6
289
16.67%
Add the exponents and keep the base 7^3 x 7^5 = 7^8

49. 1/6
2.23
= the square root of 9 = 3
16.67%
...yields a negative result (-1)^57 = -1

50. 12^2
625
...yields a negative result (-1)^57 = -1
8 - 16 - 24 - 32 - 40 - 48 - 56 - 64 - 72 - 80 - 88 - 96 - 104 - 112 - 120
144