Ratios & Proportions
Compare quantities, solve proportions, and apply ratio thinking to real-world rates and scale. Grades 4–5.
Grade 4Grade 5
Introduction to Ratios
Grade 4Learn ratio notation (a:b, a/b, 'a to b'), compare quantities, and equivalent ratios
Proportions & Scale
Grades 4–5Solve proportions, calculate unit rates, use scale factors and scale drawings
What is a Ratio?
A ratio is a comparison of two quantities. If a bag has 3 red marbles and 5 blue marbles, the ratio of red to blue is 3:5.
3 : 5
Colon notation
3 to 5
Word notation
3/5
Fraction notation
Real-World Ratios
🍪 Recipes2 cups flour : 1 cup sugar → scale up or down
🗺️ MapsScale 1:50,000 means 1cm = 500m in real life
🚗 Speed60 km per 1 hour = a unit rate
💰 Value$3 for 2 items → find cost of 5 items