Warm-Up 1
Day 2: Rational Number Operations
Review operations with fractions, decimals, integers, and negative rational numbers.
Student Goal
I can solve problems with positive and negative rational numbers.
Why It Matters
Rational number fluency supports 8th grade work with equations, slope, scientific notation, and real-world problem solving.
Warm-Up
Warm-Up 2
Find -3 x 8.
Warm-Up 3
Find 1/2 + 1/4.
Short Lesson
Standard Focus
NC.8.NS: The Number System
Student-Friendly Standard Goal
I can use rational numbers to solve problems and explain the reasonableness of my answer.
- Rational numbers include integers, fractions, and decimals that can be written as fractions.
- For addition and subtraction, think about direction on a number line or combine values carefully.
- For multiplication and division, same signs give a positive result and different signs give a negative result.
Guided Examples
Guided Example 1
Temperature Change
The temperature is -3 degrees. It drops 8 degrees, then rises 5 degrees. What is the final temperature?
Step 1
-3 - 8
What is the temperature after the drop?
Guided Example 2
Fraction Product
A recipe uses 3/4 cup of oats for one batch. How many cups are needed for 2 batches?
Step 1
2 x 3/4
What operation matches two equal batches?
Practice
Problem 1
Find -9 + 4.
Problem 2
Find -2.5 - 1.5.
Problem 3
Find -6 x -4.
Problem 4
A diver is at -12 feet and rises 7 feet. What is the new position?
Problem 5
Which next step is best for 1/3 + 1/6?
Reflection
How are you feeling about today's skill?
Optional reflection: Which rational number operation do you want to keep practicing?