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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. 1/2
1.41
{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}
50%
125

2. 2^9
4
75%
Multiply the exponents 7^2(^3) = 7^6
512

3. Examples of roots simplification
50%
27
√25.16 = √25 . √16 = 5.4 - √50 . √18 = √50.18 = √900 = 30 - √144:16 = √144 : √16 = 12/4 = 3
64

4. √ 169
128
{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}
Take the reciprocal of the base and change the sign of the exponent (2)^-2 = 1^2/2^2 = 1/4
13

5. (a+b)^2 =
25
324
A^2 + 2ab + b^2
1296

6. 18^2
125
196
25
324

7. 1/6
16.67%
40%
12.50%
16

8. 4^4
256
169
You cannot simplify this one
361

9. 1/8
128
12.50%
16.66%
1.73

10. 2^5
32
25%
324
1.41

11. √25+16 = √41
2.23
40%
You cannot simplify this one
256

12. 2^6
12.50%
169
1.41
64

13. A^2-B^2
169
(A+B)(A-B)
8
625

14. 2^2
4
15 - 30 - 45 - 60 - 75 - 90 - 105 - 120
...yields a smaller result (1/2)^2 = 1/4
8

15. 13^2
169
125
(A+B)(A-B)
4

16. 1/4
1296
75%
87.50%
25%

17. a^3+b^3
81
2
(a+b)(a^2-ab+b^2)
16

18. 1/20
256
5%
50%
...yields a negative result (-1)^57 = -1

19. Multiples of 12
243
5%
196
12 - 24 - 36 - 48 - 60 - 72 - 84 - 96 - 108 - 120

20. 19^2
256
361
Multiply the exponents 7^2(^3) = 7^6
...yields a positive result (-1)^2 = 1

21. (a-b)^2 =
16.67%
Subtract the exponents and keep the base the same 4^5/4^2 = 4^3
A^2 - 2ab + b^2
...yields a positive result (-1)^2 = 1

22. √ 4
2
Subtract the exponents and keep the base the same 4^5/4^2 = 4^3
225
256

23. Simplifying a root
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
5%
12 - 24 - 36 - 48 - 60 - 72 - 84 - 96 - 108 - 120
144

24. 4^3
81
243
27
64

25. 7/8
5%
(a-b)(a^2+ab+b^2)
32
87.50%

26. 11^2
25%
Subtract the exponents and keep the base the same 4^5/4^2 = 4^3
5%
121

27. 1/12
...yields a positive result (-1)^2 = 1
8.33%
8
You cannot simplify this one

28. 15^2
121
You cannot simplify this one
225
{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}

29. to multiple powers with the same base...
81
Add the exponents and keep the base 7^3 x 7^5 = 7^8
1024
27

30. 2/5
Take the reciprocal of the base and change the sign of the exponent (2)^-2 = 1^2/2^2 = 1/4
50%
40%
8

31. a negative number raised to an odd power...
...yields a negative result (-1)^57 = -1
27
324
243

32. 12^2
...yields a positive result (-1)^2 = 1
144
12.50%
You cannot simplify this one

33. a negative number raised to an even power...
...yields a positive result (-1)^2 = 1
16
8.33%
(a-b)(a^2+ab+b^2)

34. 2^10
13
1024
87.50%
You cannot simplify this one

35. √ 5
40%
2.23
12 - 24 - 36 - 48 - 60 - 72 - 84 - 96 - 108 - 120
75%

36. 2^7
4
128
243
...yields a positive result (-1)^2 = 1

37. 5^5
A^2 - 2ab + b^2
3125
25
1.41

38. 2^3
144
256
8
12 - 24 - 36 - 48 - 60 - 72 - 84 - 96 - 108 - 120

39. 16^2
256
= the cube root of 8 = 2
5%
8

40. 17^2
16.66%
12 - 24 - 36 - 48 - 60 - 72 - 84 - 96 - 108 - 120
= the square root of 9 = 3
289

41. Prime Numbers between 1 - 100 (total of 25)
...yields a negative result (-1)^57 = -1
{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}
83.33%
5%

42. 5^4
625
{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
196

43. 6^4
12.50%
1296
20%
2

44. 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
1.41
256
8

45. 5/6
...yields a negative result (-1)^57 = -1
8 - 16 - 24 - 32 - 40 - 48 - 56 - 64 - 72 - 80 - 88 - 96 - 104 - 112 - 120
83.33%
...yields a positive result (-1)^2 = 1

46. to multiple powers (or raise a power to a power)
2
Multiply the exponents 7^2(^3) = 7^6
Add the exponents and keep the base 7^3 x 7^5 = 7^8
8

47. √ 6
13
3125
169
2.449

48. a^3-b^3
20%
1024
(a-b)(a^2+ab+b^2)
(a+b)(a^2-ab+b^2)

49. 3^4
81
196
25
1.41

50. √ 3
625
243
1.73
256