How to Do Integers, Step by Step (With Examples)

A MathHelp247 guide · Integers · Grades 6–8

Integers are whole numbers that can be positive, negative or zero — like −3, 0 and 5. The tricky part is keeping track of the signs. Once you know a few rules, every operation becomes straightforward.

Picture a number line

Negative numbers sit to the left of zero and positives to the right. Adding a positive moves you right; adding a negative moves you left. Keeping this picture in mind makes the rules feel natural.

Adding integers

Same signs: add the values and keep the sign. Different signs: subtract the smaller value from the larger, and take the sign of the number that was further from zero.

Subtracting integers

The key move: subtracting is the same as adding the opposite. Change the subtraction to addition and flip the sign of the second number, then use the addition rules.

Multiplying and dividing integers

For both multiplication and division, work out the values first, then apply the sign rule: same signs give a positive, different signs give a negative.

A quick way to remember the sign rule

For times and divide, count the negatives. An even number of negatives gives a positive answer; an odd number gives a negative answer.

Common mistakes to avoid

• Two minuses next to each other. Subtracting a negative becomes adding: 5 − (−2) = 5 + 2.
• Mixing up the rules. The "same sign = positive" rule is for multiplying and dividing — not for adding.
• Dropping the sign. Always decide the sign of your answer before you write it down.