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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. 1/12
8.33%
16.66%
13
12 - 24 - 36 - 48 - 60 - 72 - 84 - 96 - 108 - 120

2. a^3-b^3
(a-b)(a^2+ab+b^2)
Add the exponents and keep the base 7^3 x 7^5 = 7^8
= the cube root of 8 = 2
128

3. 6^3
1296
(a+b)(a^2-ab+b^2)
216
32

4. 2^7
216
1024
= the cube root of 8 = 2
128

5. 1/4
(A+B)(A-B)
25%
256
A^2 - 2ab + b^2

6. a negative number raised to an even power...
128
196
(a+b)(a^2-ab+b^2)
...yields a positive result (-1)^2 = 1

7. 3^5
8
256
243
You cannot simplify this one

8. A^2-B^2
7776
(A+B)(A-B)
256
12 - 24 - 36 - 48 - 60 - 72 - 84 - 96 - 108 - 120

9. √ 5
25
196
243
2.23

10. raising a fraction between zero and 1 to a power...
...yields a smaller result (1/2)^2 = 1/4
125
196
121

11. 4^3
20%
Subtract the exponents and keep the base the same 4^5/4^2 = 4^3
196
64

12. 18^2
324
81
Subtract the exponents and keep the base the same 4^5/4^2 = 4^3
7776

13. 2^3
16
625
8
(a+b)(a^2-ab+b^2)

14. Multiples of 8
64
15 - 30 - 45 - 60 - 75 - 90 - 105 - 120
8 - 16 - 24 - 32 - 40 - 48 - 56 - 64 - 72 - 80 - 88 - 96 - 104 - 112 - 120
289

15. Multiples of 12
12 - 24 - 36 - 48 - 60 - 72 - 84 - 96 - 108 - 120
...yields a positive result (-1)^2 = 1
25
1.41

16. (a+b)^2 =
√25.16 = √25 . √16 = 5.4 - √50 . √18 = √50.18 = √900 = 30 - √144:16 = √144 : √16 = 12/4 = 3
A^2 + 2ab + b^2
1024
625

17. to divide powers with the same base...
Subtract the exponents and keep the base the same 4^5/4^2 = 4^3
87.50%
128
256

18. 5/6
A^2 + 2ab + b^2
8.33%
7776
83.33%

19. 6^5
1024
1.41
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

20. 19^2
2.449
16.67%
(a-b)(a^2+ab+b^2)
361

21. √ 169
...yields a positive result (-1)^2 = 1
13
128
512

22. Examples of roots simplification
5%
= the cube root of 8 = 2
√25.16 = √25 . √16 = 5.4 - √50 . √18 = √50.18 = √900 = 30 - √144:16 = √144 : √16 = 12/4 = 3
16.67%

23. √ 4
2
256
169
216

24. 1/6
289
16.67%
A^2 + 2ab + b^2
83.33%

25. 2^10
256
1024
50%
...yields a smaller result (1/2)^2 = 1/4

26. (a-b)^2 =
25
Multiply the exponents 7^2(^3) = 7^6
A^2 - 2ab + b^2
1.41

27. 2^9
75%
512
You cannot simplify this one
2

28. 1/6
81
16.66%
A^2 - 2ab + b^2
40%

29. what happens when an exponent is negative?
A^2 - 2ab + b^2
15 - 30 - 45 - 60 - 75 - 90 - 105 - 120
Take the reciprocal of the base and change the sign of the exponent (2)^-2 = 1^2/2^2 = 1/4
2.23

30. √ 625
324
169
= the square root of 9 = 3
25

31. a^3+b^3
83.33%
(a+b)(a^2-ab+b^2)
87.50%
...yields a smaller result (1/2)^2 = 1/4

32. 5^4
7776
625
144
256

33. to multiple powers with the same base...
A^2 - 2ab + b^2
125
Add the exponents and keep the base 7^3 x 7^5 = 7^8
1.73

34. a negative number raised to an odd power...
8.33%
Add the exponents and keep the base 7^3 x 7^5 = 7^8
...yields a negative result (-1)^57 = -1
= the cube root of 8 = 2

35. 5^5
1.41
3125
2.449
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

36. √ 2
16.66%
(a+b)(a^2-ab+b^2)
256
1.41

37. 2^4
81
16
121
289

38. 2^8
256
83.33%
12 - 24 - 36 - 48 - 60 - 72 - 84 - 96 - 108 - 120
27

39. 2^2
1024
4
8 - 16 - 24 - 32 - 40 - 48 - 56 - 64 - 72 - 80 - 88 - 96 - 104 - 112 - 120
25%

40. 16^2
216
2.23
121
256

41. 17^2
225
2.449
289
You cannot simplify this one

42. √ 3
1.73
(a-b)(a^2+ab+b^2)
256
...yields a positive result (-1)^2 = 1

43. 1/20
27
5%
20%
40%

44. Prime Numbers between 1 - 100 (total of 25)
75%
243
A^2 - 2ab + b^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}

45. 1/8
1.73
125
16.66%
12.50%

46. Simplifying a root
16.67%
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
75%
(a-b)(a^2+ab+b^2)

47. 12^2
144
1024
√25.16 = √25 . √16 = 5.4 - √50 . √18 = √50.18 = √900 = 30 - √144:16 = √144 : √16 = 12/4 = 3
27

48. Express 9^1/2 as a radical
5%
= the square root of 9 = 3
64
You cannot simplify this one

49. Multiples of 15
169
361
2
15 - 30 - 45 - 60 - 75 - 90 - 105 - 120

50. 6^4
8
1296
128
3125