Pre-Algebra · Grades 6 to 8
Integers and negative numbers
Add and subtract positive and negative whole numbers.
The idea
An integer is a whole number. It can be positive, negative or zero. On the number line, positive numbers sit to the right of zero and negative numbers sit to the left.
Adding a positive number moves right. Adding a negative number moves left. Subtracting a number gives the same result as adding its opposite.
Worked examples
- How to Add and Subtract Negative Numbers Work out -7 + 3 - (-4) with the number line. Four steps, the reasons for each move, and the sign mistakes to avoid.
- How to Use the Order of Operations (PEMDAS) Work through 4 + 3 x 2^2 - 6 / 3 in four steps. See which operation goes first, why each step is allowed, and the order mistakes to avoid.
- How to Evaluate an Algebraic Expression Evaluate 2x^2 + 3x - 1 when x = 3. Substitute the value, follow the order of operations, and see the mistakes that cost marks.
Practice this topic
3 problems with answers.