Subtracting a Negative
Part of the Numbers & Operations section of Coddy's Pre-Algebra journey. Lesson 24 of 60.
What happens when you subtract a negative number? Use the rule from the last lesson: subtracting is adding the opposite. The opposite of -4 is 4, so 2 - (-4) is 2 + 4, which is 6. Two minus signs in a row become a plus.
On the number line, subtracting moves you left, and taking away a negative undoes a move left, so it moves you right. In money: if someone cancels a 4 dollar debt you owe, you are 4 dollars better off. The same holds below zero: -7 - (-2) is -7 + 2, which is -5.
Challenge
Work out -6 - (-9). First rewrite it as an addition, then type the result.
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