Zero Pairs
Part of the Numbers & Operations section of Coddy's Pre-Algebra journey. Lesson 20 of 60.
A number plus its opposite is always 0. 4 + (-4) is 0: you walk 4 steps right and 4 steps left, and end where you started. A number and its opposite are called a zero pair.
In a longer sum, look for zero pairs before doing anything else. In -6 + 9 + 6, the -6 and the 6 cancel, so the whole sum is just 9. They do not have to sit next to each other: a sum can be added in any order, for negative numbers just as for positive ones.
Why bother? Every number you cancel is a number you never have to add, and fewer steps means fewer chances to slip. Spotting a zero pair turns a three-number sum into one number.
Challenge
Work out -11 + 7 + 11 in one line. Look for a zero pair first.
Try it yourself
Simplify the expression
Test yourselfThis lesson includes a short quiz. Start the lesson to answer it and track your progress.
All lessons in Numbers & Operations
1Working on the Board
Your First AnswerType the Next LineOne Line at a TimeDots and BarsFriendly ProductsRecap: Board Work4Adding Integers
Adding Two NegativesDifferent SignsZero PairsAdding Several IntegersRecap: Adding Integers2Order of Operations
Multiply Before AddingLeft to RightParentheses FirstBrackets Inside BracketsThe Fraction Bar GroupsRecap: Order of Operations5Subtracting Integers
Add the OppositeSubtracting a NegativePlus and Minus in a RowDistance Between NumbersRecap: Subtracting Integers