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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. Multiples of 12
...yields a smaller result (1/2)^2 = 1/4
12 - 24 - 36 - 48 - 60 - 72 - 84 - 96 - 108 - 120
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
2.23

2. 3^5
√25.16 = √25 . √16 = 5.4 - √50 . √18 = √50.18 = √900 = 30 - √144:16 = √144 : √16 = 12/4 = 3
243
Take the reciprocal of the base and change the sign of the exponent (2)^-2 = 1^2/2^2 = 1/4
625

3. 5^4
625
...yields a positive result (-1)^2 = 1
1.41
87.50%

4. 3^4
81
1296
(a+b)(a^2-ab+b^2)
5%

5. Express 9^1/2 as a radical
256
You cannot simplify this one
= the square root of 9 = 3
...yields a smaller result (1/2)^2 = 1/4

6. 2^7
64
20%
8.33%
128

7. a^3-b^3
256
7776
40%
(a-b)(a^2+ab+b^2)

8. to divide powers with the same base...
512
Take the reciprocal of the base and change the sign of the exponent (2)^-2 = 1^2/2^2 = 1/4
1024
Subtract the exponents and keep the base the same 4^5/4^2 = 4^3

9. what happens when an exponent is negative?
121
25
512
Take the reciprocal of the base and change the sign of the exponent (2)^-2 = 1^2/2^2 = 1/4

10. √ 4
7776
√25.16 = √25 . √16 = 5.4 - √50 . √18 = √50.18 = √900 = 30 - √144:16 = √144 : √16 = 12/4 = 3
2
64

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

12. 2/5
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
16
12.50%
40%

13. a negative number raised to an even power...
(a+b)(a^2-ab+b^2)
A^2 - 2ab + b^2
81
...yields a positive result (-1)^2 = 1

14. Multiples of 8
121
√25.16 = √25 . √16 = 5.4 - √50 . √18 = √50.18 = √900 = 30 - √144:16 = √144 : √16 = 12/4 = 3
8 - 16 - 24 - 32 - 40 - 48 - 56 - 64 - 72 - 80 - 88 - 96 - 104 - 112 - 120
= the cube root of 8 = 2

15. 1/20
5%
216
25
2

16. √ 5
1.41
Subtract the exponents and keep the base the same 4^5/4^2 = 4^3
2.23
361

17. 6^4
25%
7776
1296
64

18. 19^2
1024
361
25%
= the cube root of 8 = 2

19. 2^4
= the square root of 9 = 3
75%
16
13

20. 5^3
(a-b)(a^2+ab+b^2)
125
243
8

21. 13^2
7776
225
169
5%

22. 5/6
8 - 16 - 24 - 32 - 40 - 48 - 56 - 64 - 72 - 80 - 88 - 96 - 104 - 112 - 120
83.33%
27
1.73

23. 1/5
20%
64
Take the reciprocal of the base and change the sign of the exponent (2)^-2 = 1^2/2^2 = 1/4
Multiply the exponents 7^2(^3) = 7^6

24. 2^6
64
4
A^2 - 2ab + b^2
75%

25. 2^10
{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 negative result (-1)^57 = -1
8 - 16 - 24 - 32 - 40 - 48 - 56 - 64 - 72 - 80 - 88 - 96 - 104 - 112 - 120
1024

26. Simplifying a root
2
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
Subtract the exponents and keep the base the same 4^5/4^2 = 4^3
128

27. 5^5
12.50%
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
83.33%
3125

28. 1/6
361
16.66%
2.23
5%

29. (a+b)^2 =
243
A^2 + 2ab + b^2
169
16

30. 15^2
256
13
1.73
225

31. √ 625
625
25
(a-b)(a^2+ab+b^2)
...yields a positive result (-1)^2 = 1

32. 4^5
27
81
8.33%
1024

33. A^2-B^2
A^2 - 2ab + b^2
(A+B)(A-B)
5%
64

34. 1/8
25
16.66%
40%
12.50%

35. Multiples of 15
625
144
1.41
15 - 30 - 45 - 60 - 75 - 90 - 105 - 120

36. 6^5
243
75%
81
7776

37. a^3+b^3
1296
125
A^2 + 2ab + b^2
(a+b)(a^2-ab+b^2)

38. raising a fraction between zero and 1 to a power...
1024
361
...yields a smaller result (1/2)^2 = 1/4
324

39. √ 3
Subtract the exponents and keep the base the same 4^5/4^2 = 4^3
1.73
289
8

40. 2^8
256
Subtract the exponents and keep the base the same 4^5/4^2 = 4^3
125
87.50%

41. Prime Numbers between 1 - 100 (total of 25)
...yields a negative result (-1)^57 = -1
(A+B)(A-B)
196
{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}

42. to multiple powers with the same base...
2.449
Take the reciprocal of the base and change the sign of the exponent (2)^-2 = 1^2/2^2 = 1/4
32
Add the exponents and keep the base 7^3 x 7^5 = 7^8

43. 2^9
121
1024
256
512

44. 1/12
8.33%
7776
A^2 + 2ab + b^2
243

45. √25+16 = √41
Multiply the exponents 7^2(^3) = 7^6
You cannot simplify this one
169
125

46. 4^4
...yields a smaller result (1/2)^2 = 1/4
A^2 + 2ab + b^2
256
Multiply the exponents 7^2(^3) = 7^6

47. 16^2
256
...yields a positive result (-1)^2 = 1
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
12 - 24 - 36 - 48 - 60 - 72 - 84 - 96 - 108 - 120

48. 3/4
75%
256
15 - 30 - 45 - 60 - 75 - 90 - 105 - 120
225

49. to multiple powers (or raise a power to a power)
{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}
25%
Multiply the exponents 7^2(^3) = 7^6
16.67%

50. 7/8
169
8 - 16 - 24 - 32 - 40 - 48 - 56 - 64 - 72 - 80 - 88 - 96 - 104 - 112 - 120
1024
87.50%