GRE is a difficult test, but it is a very learnable test. In this article, we provide you with some easy to remember and important points to remember in the Arithmetic section for GRE Math. Make sure you practice these concepts regularly to master the GRE.
- A prime number is an integer that is divisible only by itlself and 1.
- An even number is divisible by 2, and can be written as 2x.
- An odd number is not divisible by 2, and can be written as 2x + 1.
- Division by zero is undefined.
- Perfect squares: 1, 4, 9, 16, 25, 36, 49, 64, 81 . . .
- Perfect cubes: 1, 8, 27, 64, 125 . . .
- If the last digit of a integer is 0, 2, 4, 6, or 8, then it is divisible by 2.
- An integer is divisible by 3 if the sum of its digits is divisible by 3.
- If the last digit of a integer is 0 or 5, then it is divisible by 5.
- Consecutive integers are written as x, x + 1, x + 2,..
- Consecutive even or odd integers are written as x, x + 2, x + 4,..
- The integer zero is neither positive nor negative, but it is even: 0 = 2 ⋅ 0.
- Commutative property: x + y = y + x. Example: 5 + 4 = 4 + 5.
- Associative property: (x + y) + z = x + (y + z). Example: (1 + 2) + 3 = 1 + (2 + 3).
- Order of operations: Parentheses, Exponents, Multiplication, Division, Addition, Subtraction.
- Common measurements: 1 foot = 12 inches, 1 yard = 3 feet, 1 quart = 2 pints, 1 gallon = 4 quarts, 1 pound = 16 ounces
- The remainder is 'r' when p is divided by q, i.e. p = qz + r; the integer z is called the quotient.
- Miscellaneous Properties of Positive and Negative Numbers:
A. The product (quotient) of positive numbers is positive.
B. The product (quotient) of a positive number and a negative number is negative.
C. The product (quotient) of an even number of negative numbers is positive.
D. The product (quotient) of an odd number of negative numbers is negative.
E. The sum of negative numbers is negative.
F. A number raised to an even exponent is greater than or equal to zero.
even x even = even
odd x odd = odd
even x odd = even
even + even = even
odd + odd = even
even + odd = odd