ARITHMETIC : Integers, fractions..
- Integers : ..-3,-2,-1,0,1,2,...
- 0 is neither neither positive or negative. 0 is even number.
- real numbers are integers and have decimal values between them..
- a0=1, 1/an=a-n
- The absolute value of a number N, denoted by N , is defined to be N if N
is positive or zero and -N if N is negative. Example |-5| =5
- Integer divisible by 2 is called even integer (including 0 and 2). Examples are -8,-6,-4,-2,0,2,4,6,8
- Factors of a number are it's divisors. For instance, the factors of 21 are 3 and 7, because 3*7 = 21.
- The greatest common divisor (or greatest common factor) of two nonzero integers x and y is the
greatest positive integer that is a divisor of both x and y. For example GCF of 30 and 45 is 15, GCF of 60 and 90 is 30.
- A prime number is an integer greater than 1 that has only two positive divisors: 1 and itself, examples are 2,3,5,7,11,13,17 (remember 2 is a prime number)
- Fractions are numbers in the form (x/y) where y is never 0. Examples: 3/5, -7/8
- Exponents and roots. (you will always find few questions on this)