# GMAT: Quick Math & Formulas

## 70 terms

4

8

16

32

64

128

256

512

1024

121

144

169

196

225

256

289

324

361

27

81

243

64

256

1024

125

625

3125

216

1296

7776

1.41

1.73

2

2.23

N/A

### Prime Numbers between 1 - 100 (total of 25)

{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}

### 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 inside/outside are linked by multiplication or division

Examples of roots simplification:
√25.16 = √25 . √16 = 5.4
√50 . √18 = √50.18 = √900 = 30
√144:16 = √144 : √16 = 12/4 = 3
√25+16 = √41  you cannot simplify this one

50%

25%

40%

5%

12.50%

16.67%

8.33%

87.50%

75%

20%

16.66%

83.33%

### Multiples of 8

8, 16, 24, 32, 40, 48, 56, 64, 72, 80, 88, 96, 104, 112, 120

### Multiples of 12

12, 24, 36, 48, 60, 72, 84, 96, 108, 120

### Multiples of 15

15, 30, 45, 60, 75, 90, 105, 120

25

13

a^2 + 2ab + b^2

a^2 - 2ab + b^2

(A+B)(A-B)

### a^3+b^3

(a+b)(a^2-ab+b^2)

### a^3-b^3

(a-b)(a^2+ab+b^2)

2.449

### to multiple powers with the same base...

add the exponents and keep the base 7^3 x 7^5 = 7^8

### to divide powers with the same base...

subtract the exponents and keep the base the same 4^5/4^2 = 4^3

### to multiple powers (or raise a power to a power)

multiply the exponents 7^2(^3) = 7^6

### a negative number raised to an even power...

...yields a positive result (-1)^2 = 1

### a negative number raised to an odd power...

...yields a negative result (-1)^57 = -1

### raising a fraction between zero and 1 to a power...

...yields a smaller result (1/2)^2 = 1/4

### 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

### Express 9^1/2 as a radical

= the square root of 9 = 3

### Express 8^1/3 as a radical

= the cube root of 8 = 2