Test your basic knowledge |

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. 5^4
128
196
Add the exponents and keep the base 7^3 x 7^5 = 7^8
625

2. √ 2
2.449
216
1.41
(a-b)(a^2+ab+b^2)

3. a^3+b^3
243
(a+b)(a^2-ab+b^2)
A^2 + 2ab + b^2
2.449

4. 3^4
15 - 30 - 45 - 60 - 75 - 90 - 105 - 120
7776
1.73
81

5. 5^5
256
512
3125
243

6. 12^2
87.50%
144
256
324

7. to divide powers with the same base...
...yields a positive result (-1)^2 = 1
Subtract the exponents and keep the base the same 4^5/4^2 = 4^3
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
1296

8. Express 8^1/3 as a radical
196
1024
= the cube root of 8 = 2
A^2 - 2ab + b^2

9. 6^3
121
216
16
16.67%

10. 1/12
8.33%
12 - 24 - 36 - 48 - 60 - 72 - 84 - 96 - 108 - 120
32
= the cube root of 8 = 2

11. 16^2
256
2.23
√25.16 = √25 . √16 = 5.4 - √50 . √18 = √50.18 = √900 = 30 - √144:16 = √144 : √16 = 12/4 = 3
4

12. 4^3
125
64
40%
128

13. 2^4
16
256
64
50%

14. 13^2
2.23
169
121
64

15. 1/20
15 - 30 - 45 - 60 - 75 - 90 - 105 - 120
5%
125
12 - 24 - 36 - 48 - 60 - 72 - 84 - 96 - 108 - 120

16. 3/4
87.50%
196
4
75%

17. Prime Numbers between 1 - 100 (total of 25)
16
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
{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}
125

18. 1/8
= the cube root of 8 = 2
12.50%
169
8 - 16 - 24 - 32 - 40 - 48 - 56 - 64 - 72 - 80 - 88 - 96 - 104 - 112 - 120

19. 2/5
40%
16.67%
20%
= the square root of 9 = 3

20. 4^4
1.41
256
...yields a smaller result (1/2)^2 = 1/4
1296

21. (a+b)^2 =
(A+B)(A-B)
16.66%
5%
A^2 + 2ab + b^2

22. 5/6
83.33%
50%
13
8.33%

23. 3^3
27
= the cube root of 8 = 2
16
2.449

24. 6^4
...yields a smaller result (1/2)^2 = 1/4
20%
196
1296

25. √ 4
64
87.50%
(A+B)(A-B)
2

26. 2^7
...yields a positive result (-1)^2 = 1
40%
128
256

27. 2^10
Take the reciprocal of the base and change the sign of the exponent (2)^-2 = 1^2/2^2 = 1/4
1.73
324
1024

28. 1/5
2.449
8.33%
20%
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

29. 1/4
A^2 + 2ab + b^2
81
25%
Take the reciprocal of the base and change the sign of the exponent (2)^-2 = 1^2/2^2 = 1/4

30. √ 3
7776
1.73
= the cube root of 8 = 2
...yields a smaller result (1/2)^2 = 1/4

31. 2^8
{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}
8.33%
256
75%

32. √ 6
Multiply the exponents 7^2(^3) = 7^6
2.449
16
= the cube root of 8 = 2

33. 1/6
Add the exponents and keep the base 7^3 x 7^5 = 7^8
= the cube root of 8 = 2
1024
16.67%

34. 11^2
...yields a negative result (-1)^57 = -1
32
121
= the cube root of 8 = 2

35. 5^3
216
125
361
144

36. 19^2
256
1296
361
1024

37. √ 5
1024
...yields a positive result (-1)^2 = 1
2.23
...yields a smaller result (1/2)^2 = 1/4

38. A^2-B^2
...yields a positive result (-1)^2 = 1
243
15 - 30 - 45 - 60 - 75 - 90 - 105 - 120
(A+B)(A-B)

39. 3^5
{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}
1.73
...yields a positive result (-1)^2 = 1
243

40. 2^2
A^2 + 2ab + b^2
87.50%
4
Take the reciprocal of the base and change the sign of the exponent (2)^-2 = 1^2/2^2 = 1/4

41. 14^2
196
25
1024
144

42. 7/8
87.50%
16
16.66%
...yields a negative result (-1)^57 = -1

43. what happens when an exponent is negative?
Add the exponents and keep the base 7^3 x 7^5 = 7^8
50%
Take the reciprocal of the base and change the sign of the exponent (2)^-2 = 1^2/2^2 = 1/4
7776

44. 18^2
32
1.41
40%
324

45. a negative number raised to an even power...
2.23
87.50%
...yields a positive result (-1)^2 = 1
1024

46. Examples of roots simplification
40%
361
√25.16 = √25 . √16 = 5.4 - √50 . √18 = √50.18 = √900 = 30 - √144:16 = √144 : √16 = 12/4 = 3
7776

47. Multiples of 15
243
216
144
15 - 30 - 45 - 60 - 75 - 90 - 105 - 120

48. 4^5
243
You cannot simplify this one
64
1024

49. Simplifying a root
50%
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}
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. 2^9
512
256
5%
√25.16 = √25 . √16 = 5.4 - √50 . √18 = √50.18 = √900 = 30 - √144:16 = √144 : √16 = 12/4 = 3