Odds & Evens

Things one must know:

• Add or subtract two odds or two evens, the result will be even.
• Add or subtract an odd with an even, the result will be odd.
• When multiplying, if any of the integers is even, the result will be even.
• When multiplying, if none of the integers is even, the result will be odd.
• Divisibility rules (see MGMAT NP p30)
• Set up a table listing all the possible odd/even scenarios if you are dealing with multiple variables that can be odd or even.
• Odd integers leave a remainder of 1 after division by 2
• Even integers leave a remainder of 0 after division by 2
• An arbitrary even number can be written as 2n, where n is any integer
• An arbitrary odd number can be written as 2n + 1 or 2n - 1, where n is any integer