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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. Express 8^1/3 as a radical
= the cube root of 8 = 2
20%
Subtract the exponents and keep the base the same 4^5/4^2 = 4^3
1.41

2. 5^4
87.50%
8.33%
625
Add the exponents and keep the base 7^3 x 7^5 = 7^8

3. 16^2
144
2.449
256
225

4. 1/5
20%
40%
243
83.33%

5. 2^2
Multiply the exponents 7^2(^3) = 7^6
4
A^2 - 2ab + b^2
20%

6. √25+16 = √41
You cannot simplify this one
13
Add the exponents and keep the base 7^3 x 7^5 = 7^8
1.41

7. 2^9
81
512
121
216

8. 17^2
64
169
289
40%

9. 4^5
216
121
1024
144

10. 14^2
A^2 + 2ab + b^2
121
256
196

11. √ 6
2.449
83.33%
27
128

12. √ 169
13
16.66%
(A+B)(A-B)
1.73

13. 1/2
50%
1.73
2
...yields a negative result (-1)^57 = -1

14. 1/8
32
15 - 30 - 45 - 60 - 75 - 90 - 105 - 120
12.50%
A^2 + 2ab + b^2

15. 3/4
144
= the square root of 9 = 3
(A+B)(A-B)
75%

16. 2^6
...yields a smaller result (1/2)^2 = 1/4
75%
87.50%
64

17. A^2-B^2
(A+B)(A-B)
8.33%
4
1024

18. Multiples of 15
1024
243
15 - 30 - 45 - 60 - 75 - 90 - 105 - 120
40%

19. 4^4
16.66%
125
256
169

20. Prime Numbers between 1 - 100 (total of 25)
625
75%
64
{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}

21. 2^8
20%
256
27
1.73

22. 1/12
8.33%
25%
625
169

23. 6^4
256
1296
169
324

24. raising a fraction between zero and 1 to a power...
...yields a smaller result (1/2)^2 = 1/4
196
8
2.23

25. 19^2
8 - 16 - 24 - 32 - 40 - 48 - 56 - 64 - 72 - 80 - 88 - 96 - 104 - 112 - 120
Multiply the exponents 7^2(^3) = 7^6
64
361

26. 6^3
4
15 - 30 - 45 - 60 - 75 - 90 - 105 - 120
144
216

27. √ 625
25
144
Add the exponents and keep the base 7^3 x 7^5 = 7^8
{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}

28. √ 2
2
16
1.41
= the cube root of 8 = 2

29. 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}
12.50%
(a-b)(a^2+ab+b^2)
8

30. Examples of roots simplification
256
5%
3125
√25.16 = √25 . √16 = 5.4 - √50 . √18 = √50.18 = √900 = 30 - √144:16 = √144 : √16 = 12/4 = 3

31. 2^5
128
81
625
32

32. 6^5
64
(a-b)(a^2+ab+b^2)
75%
7776

33. 3^5
A^2 - 2ab + b^2
243
289
40%

34. to divide powers with the same base...
Subtract the exponents and keep the base the same 4^5/4^2 = 4^3
87.50%
144
You cannot simplify this one

35. 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
144
= the square root of 9 = 3
...yields a positive result (-1)^2 = 1

36. 5^5
3125
2.23
Subtract the exponents and keep the base the same 4^5/4^2 = 4^3
4

37. Express 9^1/2 as a radical
Multiply the exponents 7^2(^3) = 7^6
= the square root of 9 = 3
Take the reciprocal of the base and change the sign of the exponent (2)^-2 = 1^2/2^2 = 1/4
243

38. Multiples of 8
8 - 16 - 24 - 32 - 40 - 48 - 56 - 64 - 72 - 80 - 88 - 96 - 104 - 112 - 120
1296
32
= the square root of 9 = 3

39. 18^2
324
1.41
20%
32

40. 5/6
Take the reciprocal of the base and change the sign of the exponent (2)^-2 = 1^2/2^2 = 1/4
83.33%
243
32

41. 2/5
40%
7776
{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}
...yields a positive result (-1)^2 = 1

42. √ 5
64
1296
2.23
40%

43. to multiple powers with the same base...
= the square root of 9 = 3
121
Add the exponents and keep the base 7^3 x 7^5 = 7^8
1024

44. 2^10
(a-b)(a^2+ab+b^2)
16.67%
1024
81

45. 1/4
4
25%
1.73
1296

46. 7/8
40%
1296
87.50%
216

47. √ 3
1.73
196
121
25

48. a^3+b^3
(a+b)(a^2-ab+b^2)
20%
...yields a positive result (-1)^2 = 1
Take the reciprocal of the base and change the sign of the exponent (2)^-2 = 1^2/2^2 = 1/4

49. to multiple powers (or raise a power to a power)
Multiply the exponents 7^2(^3) = 7^6
225
25
40%

50. 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
7776
83.33%
(a+b)(a^2-ab+b^2)