# GRE Math Fact V.1

 What is an integer? The integers are {...-3, -2, -1, 0, 1, 2, 3...}An integer is any negative or postive number What are the sum, difference, product, and quotient of two numbers? The sum is the result of an addition.The difference is the result of subtraction.The product is the result of multiplication.The quotient is the result of division. What do we mean by the quotient and the remainder whtn one postive integer is divided by another postive integer? When 23/5 it comes out to 4 with a remainder of 3.23=4*5+3 When 35/5 the quotient is 5 and 0 is the remainder, or there is no remainder. The remainder muts be and integer that is greater than or equal to 0 and less than the number you are dividing by, What is the divisor of an integer? What is a factor of an integer? The terms divisor and factor mean the exactly the same thing.A divisor (or factor) of an integer, n, is an integer that leaves no remainder when it is divided into n. For example, the postive divisors (or factors) of 12 are: 1, 2, 3, 4, 6, and 12. What is a prime number? A prime number is a postive integer that has exactly two postive divisors, 1 and itself. What is a multiple of an integer? A multiple of an integer, n, is any integer that is the product of n and another integer. For example: 50 is a multiple of 10 since 50 = 5*10. What is an even number? What is an odd number? An even number is a integer that is a multiple of 2. An odd number is an integer that is not a multiple of 2. What is an exponent? The expression xb, x is the base and b is the exponent. What are Laws of Exponents? bmbn = bm+nbm/bn = bm-n(bm)n = bmnam * bm = (ab)mam/bm = (a/b)m What is a negative exponent? For any number, n: x-n means 1/xn What is a fractional exponent? If x is positive and n is a positive integer: x1/n means n What is the square root of a number? If x is postive, the square root of x, written , is the only postive number. What are some important properties of square roots? For any positive numbers x and y: xy = x * y and a/b = a / b If the product of two or more numbers is 0, what do you know about the numbers? If the product is equal to 0, then at least one of the factors is 0. What is the distributive law? The distributive law for any numbers a, b, c:a(b+c) = ab +ac and a(b-c) = ab-ac also if a 0: (b+c)/ a = b/a + c/a and (b-c)/a = b/a - c/a What are some important properties of 0? 0 is the only number that is neither postive nor negativeIf a is negative and b is postitive, then a<0