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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. 2^4
196
A^2 + 2ab + b^2
16
50%

2. to multiple powers (or raise a power to a power)
= the cube root of 8 = 2
Multiply the exponents 7^2(^3) = 7^6
20%
A^2 + 2ab + b^2

3. 5^4
87.50%
625
Multiply the exponents 7^2(^3) = 7^6
2.23

4. 1/2
289
50%
75%
64

5. 2^7
256
225
128
1024

6. (a-b)^2 =
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}
169
A^2 - 2ab + b^2

7. Multiples of 15
2
15 - 30 - 45 - 60 - 75 - 90 - 105 - 120
(A+B)(A-B)
512

8. 19^2
75%
83.33%
361
256

9. √ 4
144
361
125
2

10. 7/8
324
225
Multiply the exponents 7^2(^3) = 7^6
87.50%

11. 3^5
243
196
256
5%

12. 18^2
64
...yields a smaller result (1/2)^2 = 1/4
324
Subtract the exponents and keep the base the same 4^5/4^2 = 4^3

13. a^3-b^3
{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}
12 - 24 - 36 - 48 - 60 - 72 - 84 - 96 - 108 - 120
(a-b)(a^2+ab+b^2)
8 - 16 - 24 - 32 - 40 - 48 - 56 - 64 - 72 - 80 - 88 - 96 - 104 - 112 - 120

14. 2^3
83.33%
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
√25.16 = √25 . √16 = 5.4 - √50 . √18 = √50.18 = √900 = 30 - √144:16 = √144 : √16 = 12/4 = 3
8

15. 1/12
1296
243
8.33%
289

16. Multiples of 12
81
1.73
87.50%
12 - 24 - 36 - 48 - 60 - 72 - 84 - 96 - 108 - 120

17. 6^4
1296
Add the exponents and keep the base 7^3 x 7^5 = 7^8
2.23
16

18. Examples of roots simplification
12.50%
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
50%
√25.16 = √25 . √16 = 5.4 - √50 . √18 = √50.18 = √900 = 30 - √144:16 = √144 : √16 = 12/4 = 3

19. (a+b)^2 =
12 - 24 - 36 - 48 - 60 - 72 - 84 - 96 - 108 - 120
A^2 + 2ab + b^2
20%
289

20. 1/20
5%
3125
1024
64

21. 1/8
5%
361
√25.16 = √25 . √16 = 5.4 - √50 . √18 = √50.18 = √900 = 30 - √144:16 = √144 : √16 = 12/4 = 3
12.50%

22. 2^10
4
1024
32
...yields a positive result (-1)^2 = 1

23. a negative number raised to an odd power...
128
...yields a smaller result (1/2)^2 = 1/4
...yields a negative result (-1)^57 = -1
You cannot simplify this one

24. Express 9^1/2 as a radical
= the square root of 9 = 3
256
144
8

25. a^3+b^3
12 - 24 - 36 - 48 - 60 - 72 - 84 - 96 - 108 - 120
(a+b)(a^2-ab+b^2)
243
Take the reciprocal of the base and change the sign of the exponent (2)^-2 = 1^2/2^2 = 1/4

26. to multiple powers with the same base...
You cannot simplify this one
{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}
Add the exponents and keep the base 7^3 x 7^5 = 7^8
81

27. 2/5
125
40%
625
(A+B)(A-B)

28. what happens when an exponent is negative?
50%
12 - 24 - 36 - 48 - 60 - 72 - 84 - 96 - 108 - 120
125
Take the reciprocal of the base and change the sign of the exponent (2)^-2 = 1^2/2^2 = 1/4

29. to divide powers with the same base...
2.449
Subtract the exponents and keep the base the same 4^5/4^2 = 4^3
625
1296

30. 14^2
625
256
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
196

31. 6^5
...yields a negative result (-1)^57 = -1
64
7776
(a-b)(a^2+ab+b^2)

32. √ 2
512
1.41
8 - 16 - 24 - 32 - 40 - 48 - 56 - 64 - 72 - 80 - 88 - 96 - 104 - 112 - 120
243

33. 1/4
1296
32
(a-b)(a^2+ab+b^2)
25%

34. Express 8^1/3 as a radical
Take the reciprocal of the base and change the sign of the exponent (2)^-2 = 1^2/2^2 = 1/4
...yields a smaller result (1/2)^2 = 1/4
20%
= the cube root of 8 = 2

35. A^2-B^2
83.33%
125
8
(A+B)(A-B)

36. Simplifying a root
3125
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
16
25

37. 5^5
216
3125
A^2 + 2ab + b^2
16.66%

38. √25+16 = √41
You cannot simplify this one
1024
12.50%
(A+B)(A-B)

39. 11^2
16.66%
121
5%
16

40. 2^5
32
625
121
83.33%

41. 6^3
243
216
A^2 + 2ab + b^2
Add the exponents and keep the base 7^3 x 7^5 = 7^8

42. 1/5
8
7776
20%
...yields a positive result (-1)^2 = 1

43. 15^2
83.33%
5%
128
225

44. 2^2
12 - 24 - 36 - 48 - 60 - 72 - 84 - 96 - 108 - 120
(a-b)(a^2+ab+b^2)
4
Multiply the exponents 7^2(^3) = 7^6

45. 1/6
2
16.67%
64
20%

46. 3^4
25%
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
81
125

47. 2^9
512
243
You cannot simplify this one
2.449

48. Multiples of 8
8 - 16 - 24 - 32 - 40 - 48 - 56 - 64 - 72 - 80 - 88 - 96 - 104 - 112 - 120
64
144
Multiply the exponents 7^2(^3) = 7^6

49. 4^4
256
...yields a positive result (-1)^2 = 1
2.449
83.33%

50. 5/6
83.33%
1024
7776
128