Arithmetic Flashcards Preview

GMAT Quantitative > Arithmetic > Flashcards

Flashcards in Arithmetic Deck (26):
1

Integer

Any whole number, not a fraction or decimal. -1200, -43, 0, 1, 1143

2

Even integer

Any integer that gives you another integer when divided by 2.

3

Odd integer

Any integer that gives a noninteger when divided by 2.

4

Real number

Any number in the number line.

5

Divisor or Factor

For an integer N, a divisor is a positive integer that can divide into N without creating a remainder. 1, 2, 3, 4, 6 and 12 are divisor of 12. Factors are always positive.

6

Multiple

A multiple of integer N results by multiplying N with another integer. -7, 0, 7, 140 are multiples of 7.

7

Prime number

Integer only divisible by itself and 1.
2, 3, 5, 7, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47.

8

Proper fraction

Numerator < Denominator

9

Improper fraction

Numerator > Denominator

10

Mixed Number

When whole number and fraction are combined : 2(1/2), 3(3/4)

11

Divisibility by 2

Number is even

12

Divisibility by 3

Sum of the digits is divisible by 3.

13

Divisibility by 4

The last 2 digits represent a number that is divisible by 4.

14

Divisibility by 5

Last digit is a 0 or a 5.

15

Divisibility by 7

Take the last digit, double it, and substract it to the rest of the digits. If the result is divisible by 7, the original number is.

Ex : 1050. 0×2=0, 105-0=105, 105=7×15

16

Divisibility by 10

Last number is 0

17

Divisibility by 11

Take difference between sums or alternate digits. If results divisible by 11, original number is. Ex : 4862. 4+6=10, 8+2=10, 10-10=0 which is divisible by 1. 4862=11×442

18

Divisibility by 25

Last two digits divisible by 25.

19

Greatest Common Factor (GCF)

Largest number that divides evenly into each of the given numbers. Look at the prime factors to find it. Ex : 42=2×3×7, 70=2×5×7. GCF of 42 and 70 is 2×7=14

20

Least Common Multiple (LCM)

Smallest nonzero number, multiple of 2 or more given numbers. Make sure that the LCM includes the required Prime for each numbers. Ex : 42=2×3×7, 56=2×2×2×7. LCM of 42 and 56 is 2×2×2×3×7=168

21

Even and Odd integers - Sum and difference

E +/- E = E --- E +/- O = O --- O +/- O = E

22

Even and Odd integers - Product

E × E = E --- O × O = O --- E × O = E

23

Positive and Negative - Product

(+) × (+) = (+) --- (-) × (-) = (+) --- (+) × (-) = (-)

24

Units digits - Example 6.797×13.473 ?

Numbers properties : multiply the last digits and take the digit of the result. Ex: 7×3=21 so 1 will be the digit of the final number.

25

Percent Change formule

PC = ( (FV - PV) ÷ PV ) × 100, with FV and PV Future and Present Values

26

Ratios - x:y or x/y or "x to y". Example : in a class, the ratio of female to male is 1/3. What proportion of the class is female?

F:M:Total = 1:3:4 - So there proportion of female in the class is 1/4