GRADE 7 MATH — TOPIC 2-2 Find Unit Rates with Ratios of Fractions SLIDE 1 — TITLE Topic 2-2: Find Unit Rates with Ratios of Fractions Essential Question: Why is it useful to write a ratio of fractions as a unit rate? Visual theme: Colorful, modern middle-school math presentation with fraction models, ratio tables, and real-world images of biking, cooking, and measuring. ⸻ SLIDE 2 — AIM & DO NOW Aim: How can we find unit rates with ratios of fractions and use them to solve multistep problems? Do Now — Review from Topic 2-1 1. A cyclist travels 120 miles in 3 hours. What is the unit rate in miles per hour? 2. Four notebooks cost $6. What is the cost per notebook? Directions: Solve both problems. Show your work and include units. Remember: To find a unit rate, divide the first quantity by the second quantity. ⸻ SLIDE 3 — HOW TO FIND UNIT RATES WITH RATIOS OF FRACTIONS Key Idea: A unit rate tells us how much of one quantity there is for 1 unit of another quantity. Method 1: Use an Equivalent-Ratios Table Example: A cyclist travels 7 miles in (\frac14) hour. Find the unit rate. Miles 7 28 Hours (\frac14) 1 Step 1: Ask, “What do I multiply (\frac14) by to get 1?” Step 2: Multiply both quantities by 4. [ 7\times4=28 ] [ \frac14\times4=1 ] Unit rate: 28 miles per hour. Method 2: Divide by the Second Quantity Example: A cyclist travels (\frac34) mile in (\frac12) hour. Find the unit rate. Step 1: Write the division expression. [ \frac34\div\frac12 ] Step 2: Keep, change, flip. Keep the first fraction, change division to multiplication, and flip the second fraction. [ \frac34\times\frac21 ] Step 3: Multiply and simplify. [ \frac{3\times2}{4\times1} =\frac64=\frac32=1\frac12 ] Answer: (1\frac12) miles per hour. Remember! * Divide the first quantity by the second quantity. * When dividing fractions, multiply by the reciprocal. * Simplify your answer. * Always include the correct units. ⸻ SLIDE 4 — LET’S PRACTICE TOGETHER: PROBLEM 1 Find the Unit Rate A machine uses (\frac56) yard of material in (\frac13) minute. How many yards of material does it use per minute? Step 1: Write the division expression. [ \frac56\div\frac13 ] Step 2: Multiply by the reciprocal. [ \frac56\times\frac31 ] Step 3: Multiply and simplify. [ \frac{15}{6}=\frac52=2\frac12 ] Answer: (2\frac12) yards per minute. Think About It: Why did we multiply by 3 instead of dividing by 3? ⸻ SLIDE 5 — LET’S PRACTICE TOGETHER: PROBLEM 2 Find and Interpret a Unit Rate A cyclist travels (\frac34) mile in (\frac12) hour. How far can the cyclist travel in 1 hour at the same speed? Work Together 1. Write a division expression. 2. Find the reciprocal of the second fraction. 3. Multiply and simplify. 4. Explain what the answer means. Show Your Work [ \frac34\div\frac12 ] [ =\frac34\times\frac21 ] [ =\frac64=\frac32 ] Answer: (1\frac12) miles per hour. The cyclist travels (1\frac12) miles in 1 hour at the same speed. ⸻ SLIDE 6 — LET’S PRACTICE TOG