Adding Integers
Same signs add and keep the sign; different signs subtract and take the sign of the larger magnitude.
Key idea
Same signs add and keep the sign; different signs subtract and take the sign of the larger magnitude.
In depth
Same signs: add the sizes and keep the sign. Different signs: subtract the smaller size from the larger and keep the sign of the larger. On the number line, adding a negative moves left.
Worked example
−8 + 5: signs differ, 8−5 = 3, larger size is 8 (negative), so −3.
Real-world uses
- Calculating a net score when some points are lost
- Working out a temperature change across zero
Common mistake
Adding the sizes when the signs differ.
How to learn this
- Read the key idea and say it in your own words.
- Work through the worked example, then try a similar problem.
- Use the interactive lesson’s visual and mini-quiz to check the pattern.
Frequently asked questions
What is Adding Integers?
Same signs add and keep the sign; different signs subtract and take the sign of the larger magnitude. It is a topic at the intermediate level in Arithmetic & Number Sense.
Where is Adding Integers used in real life?
Real-world examples: Calculating a net score when some points are lost; Working out a temperature change across zero.
What should I learn before Adding Integers?
Make sure you are comfortable with Integers, the previous topic in Arithmetic & Number Sense.
What is a common mistake with Adding Integers?
Adding the sizes when the signs differ.
How can I practise Adding Integers?
Open the interactive lesson, play with the visual, then answer the three-question mini-quiz. Getting two right marks the topic complete.
What comes after Adding Integers?
Move on to Multiplying Integers next.
Related intermediate topics in Arithmetic & Number Sense
- Long Multiplication – Multiply by each digit of the multiplier, shift by place value, then add partial products.
- Long Division – Divide, multiply, subtract and bring down repeatedly to get the quotient.
- Factors and Multiples – Factors divide a number exactly; multiples are its products with whole numbers.
- Divisibility Rules – Quick tests: by 2 last digit even, by 3 digit-sum divisible by 3, by 5 ends 0/5, by 9 digit-sum divisible by 9.
- Prime Numbers – A prime has exactly two positive divisors: 1 and itself.
- Composite Numbers – Numbers greater than 1 with more than two factors.