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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. what happens when an exponent is negative?
Take the reciprocal of the base and change the sign of the exponent (2)^-2 = 1^2/2^2 = 1/4
12.50%
15 - 30 - 45 - 60 - 75 - 90 - 105 - 120
243

2. 3^3
16
1.41
16.66%
27

3. 2/5
256
...yields a smaller result (1/2)^2 = 1/4
40%
64

4. 1/2
8
128
5%
50%

5. 2^9
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
512
(a+b)(a^2-ab+b^2)

6. 6^3
50%
256
216
3125

7. 11^2
121
(a+b)(a^2-ab+b^2)
25
Multiply the exponents 7^2(^3) = 7^6

8. to divide powers with the same base...
Subtract the exponents and keep the base the same 4^5/4^2 = 4^3
Take the reciprocal of the base and change the sign of the exponent (2)^-2 = 1^2/2^2 = 1/4
2
(A+B)(A-B)

9. 7/8
Add the exponents and keep the base 7^3 x 7^5 = 7^8
87.50%
A^2 - 2ab + b^2
16.67%

10. A^2-B^2
64
12.50%
(A+B)(A-B)
Multiply the exponents 7^2(^3) = 7^6

11. 13^2
13
169
75%
512

12. 2^3
Take the reciprocal of the base and change the sign of the exponent (2)^-2 = 1^2/2^2 = 1/4
40%
8
289

13. 2^8
15 - 30 - 45 - 60 - 75 - 90 - 105 - 120
256
289
32

14. 2^2
256
{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}
4
Add the exponents and keep the base 7^3 x 7^5 = 7^8

15. 19^2
361
2
1.41
225

16. 1/5
= the square root of 9 = 3
361
20%
1024

17. 2^4
121
2.449
16
13

18. 2^7
15 - 30 - 45 - 60 - 75 - 90 - 105 - 120
256
16.66%
128

19. √ 4
81
75%
1.73
2

20. √ 169
{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}
13
1.73
A^2 + 2ab + b^2

21. 17^2
75%
25
361
289

22. a negative number raised to an even power...
256
27
64
...yields a positive result (-1)^2 = 1

23. 3^5
216
64
2
243

24. 3/4
...yields a negative result (-1)^57 = -1
A^2 - 2ab + b^2
2
75%

25. Express 9^1/2 as a radical
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
8.33%
= the square root of 9 = 3
1.41

26. 1/8
256
12.50%
...yields a negative result (-1)^57 = -1
1296

27. 5/6
Subtract the exponents and keep the base the same 4^5/4^2 = 4^3
83.33%
87.50%
256

28. 4^4
2.23
√25.16 = √25 . √16 = 5.4 - √50 . √18 = √50.18 = √900 = 30 - √144:16 = √144 : √16 = 12/4 = 3
81
256

29. √ 6
1.73
2.449
625
243

30. a^3+b^3
(a+b)(a^2-ab+b^2)
A^2 - 2ab + b^2
512
Add the exponents and keep the base 7^3 x 7^5 = 7^8

31. 4^3
361
64
324
Multiply the exponents 7^2(^3) = 7^6

32. Express 8^1/3 as a radical
81
4
= the cube root of 8 = 2
64

33. (a+b)^2 =
= the square root of 9 = 3
A^2 + 2ab + b^2
(a-b)(a^2+ab+b^2)
128

34. 6^5
√25.16 = √25 . √16 = 5.4 - √50 . √18 = √50.18 = √900 = 30 - √144:16 = √144 : √16 = 12/4 = 3
289
...yields a positive result (-1)^2 = 1
7776

35. 15^2
27
3125
75%
225

36. √ 5
144
= the square root of 9 = 3
2.23
512

37. √ 3
1.73
You cannot simplify this one
75%
12 - 24 - 36 - 48 - 60 - 72 - 84 - 96 - 108 - 120

38. Multiples of 15
(a+b)(a^2-ab+b^2)
15 - 30 - 45 - 60 - 75 - 90 - 105 - 120
2
40%

39. a negative number raised to an odd power...
Add the exponents and keep the base 7^3 x 7^5 = 7^8
25
...yields a negative result (-1)^57 = -1
15 - 30 - 45 - 60 - 75 - 90 - 105 - 120

40. 16^2
40%
4
= the square root of 9 = 3
256

41. 1/6
7776
16.67%
625
Subtract the exponents and keep the base the same 4^5/4^2 = 4^3

42. 6^4
...yields a positive result (-1)^2 = 1
1296
144
16.66%

43. √ 625
25
216
13
4

44. 18^2
15 - 30 - 45 - 60 - 75 - 90 - 105 - 120
(a+b)(a^2-ab+b^2)
324
256

45. 5^5
81
...yields a smaller result (1/2)^2 = 1/4
324
3125

46. 4^5
A^2 - 2ab + b^2
1024
324
16

47. 2^6
64
40%
1024
A^2 + 2ab + b^2

48. 2^5
3125
625
32
13

49. 5^4
87.50%
625
225
Multiply the exponents 7^2(^3) = 7^6

50. 3^4
4
81
8
{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}