Opposite Operation

This worksheet teaches one of the most important shortcuts in integer math: subtracting a number is the same as adding its opposite. Students are given subtraction expressions such as 8 – 5, 6 – (-4), -5 – (-8), and -20 – (-14). Before solving, they rewrite each subtraction problem as an addition problem using the opposite of the second number. This helps students see why expressions like 6 – (-4) become 6 + 4 and why subtracting a negative can cause the value to increase. The activity strengthens subtraction, opposite integers, addition, sign changes, inverse operations, and algebraic thinking while giving students a dependable strategy they can use on much harder problems later.

For parents, this rule can sound strange at first, especially when two negative signs appear together. A simple way to say it is: “Keep the first number, change subtraction to addition, and change the second number to its opposite.” So 6 – (-4) becomes 6 + 4. The first 6 stays exactly where it is. The subtraction sign becomes addition. The -4 flips to +4. Then the student solves the easier addition problem.

Key Learning Objectives

• Rewrite Subtraction as Addition: Students practice turning every subtraction expression into an equivalent addition expression.
• Find the Opposite of an Integer: Learners change positive numbers to negative numbers and negative numbers to positive numbers.
• Understand Double Negatives: Students see why subtracting a negative becomes adding a positive.
• Connect Inverse Operations: Learners recognize the relationship between addition and subtraction.

Why This Worksheet Helps

• Removes Guesswork: Students have one reliable routine instead of several confusing subtraction rules.
• Makes Double Signs Less Scary: Expressions such as -5 – (-8) become much easier once they are rewritten.
• Prepares Students for Algebra: The same rewrite strategy appears later in equations and expressions.
• Builds Conceptual Understanding: Students learn that subtraction can be understood through addition of opposites.
• Useful for Parents Too: The “keep, change, change” routine gives adults a simple way to guide the work.

Parent-Friendly Explanation

A good routine is:

Keep the first number.
Change subtraction to addition.
Change the second number to its opposite.

For example:

6 – (-4) becomes 6 + 4.

Another example:

8 – 5 becomes 8 + (-5).

Once rewritten, students can use the integer-addition rules they already know.

This worksheet is valuable because it turns a difficult-looking operation into something students have already practiced. Subtraction, addition, opposites, negative numbers, positive numbers, and inverse operations all work together in one consistent method. For parents, the most important thing is to help the child rewrite the expression correctly before trying to solve it. In classroom and homeschool settings, this activity builds a strong foundation for integer subtraction and gives students a strategy they can carry into algebra.