Adding Integers Class Notes

Class Notes Target Skill: Adding Integers If you are adding two numbers with the same sign, follow these steps: +++ + plus + -+- plus -

1. Add the numbers together. 2. Keep the same sign. Examples: Adding two positive integers together. + 7 + +8 = 1. Add numbers together = 15 2. Keep the same sign. + Final answer = + 15 Note: This problem would usually be written like this: 7 + (+8) = Why? When a positive number is the first number in an equation they usually keep the positive sign invisible. When two signs are shown together side by side, they usually separate the two side-by-side signs by using parentheses around the second number and its sign so the signs aren't accidentally merged into one sign. Like this: two minus signs - - accidentally become one long minus sign 0151— So 7 + (+8) = + 15 or just 15 Adding two negative integers together. -3+-8 or - 3 + (- 8) = 1. Add the numbers together = 11 2. Keep the same sign = Final answer = -11

Adding two integers with different signs. ++-++

+ plus - plus +

If you are adding two integers with opposite signs; one integer is positive and one integer is negative, follow these steps: 1. Subtract the two numbers (find the difference between them). Even though this is an addition problem. 2. Choose the sign that belonged to the highest number in |absolute value|. Examples: -7 + 9 or -7 + (+9) 1. Subtract the two numbers. 9 - 7 = 2 2. Choose the sign that belonged to the highest number in |absolute value| |9| > |-7| or 9 is bigger than 7 9 had a + sign in front of it. = + Final answer = +2

Another example. 3 + - 10 or 3 + (-10) or +3 + (-10) Remember, the parentheses separate the two signs so they do not become one accidentally. 1. Subtract the two numbers. 10 - 3 = 7 2. Choose the sign that belonged to the highest number in |absolute value| |3| < |-10| or 3 is less than 10, so 10 is bigger 10 had a - sign in front of it. = Final answer = -7