Integers and Rational Numbers
Exploring Negative and Positive Numbers
Integers include all positive and negative whole numbers, as well as zero. Rational numbers are numbers that can be written as fractions, including decimals that end or repeat.
Why Do We Need Negative Numbers?
Negative numbers help us describe things like temperatures below zero, debts, or going backward in time. Rational numbers let us talk about anything between whole numbers, like half a pizza!
Adding and Subtracting Integers
When you add a positive and a negative number, think of it as moving on a number line. If you subtract a bigger number from a smaller one, you'll get a negative answer.
Real-World Examples
- If the temperature is -3°C and rises by 7°C, it becomes \( -3 + 7 = 4 \)°C.
- Owing someone $5 is like having -5 dollars.
Quick Tips
- Two negatives make a positive when multiplying or dividing.
- Rational numbers include fractions like \( \frac{3}{4} \) and decimals like 0.25.
Examples
A football team loses 5 yards on one play and gains 8 yards on the next: \( -5 + 8 = 3 \) yards.
The temperature drops from 2°C to -4°C: \( 2 - 6 = -4 \).
In a Nutshell
Integers are positive and negative whole numbers; rational numbers include fractions and decimals.