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Lesson 2-4: Fraction Operations Applications

Scenario: Garden Planning - Plan and calculate garden areas using fractions!

Duration: 65-80 minutesScenario: Garden Planning

Learning Objectives

  • Solve multi-step problems involving fraction operations
  • Calculate areas and manage resources using fractions
  • Decompose complex problems into manageable steps
  • Verify solutions using different methods

Garden Planning Problem

Garden Layout Scenario

You have a garden plot that is ¾ hectare. You want to plant:

  • ⅓ of the area with roses
  • ¼ of the area with tulips
  • The rest with grass

How many hectares will be covered with grass? If each hectare of grass needs 2½ liters of water, how much water is needed for the grass area?

Problem: Multi-step area and resource calculation

Step-by-Step Solution

Step 1: Calculate areas for roses and tulips

Roses: ¾ × ⅓ = 3/12 = ¼ hectare
Tulips: ¾ × ¼ = 3/16 hectare

Step 2: Calculate grass area

Grass = Total - Roses - Tulips
Grass = ¾ - ¼ - 3/16

Step 3: Find common denominator and subtract

LCD = 16
¾ = 12/16, ¼ = 4/16
Grass = 12/16 - 4/16 - 3/16 = 5/16 hectare

Step 4: Calculate water needed

Water = 5/16 × 2½ = 5/16 × 5/2 = 25/32 liters

Answer: Grass covers 5/16 hectare and needs 25/32 liters of water.

Alternative Method: Percentage Approach

Using Fraction of Total

Step 1: Find grass as fraction of total

Grass fraction = 1 - ⅓ - ¼ = 1 - 4/12 - 3/12 = 5/12

Step 2: Calculate grass area

Grass area = ¾ × 5/12 = 15/48 = 5/16 hectare

Step 3: Calculate water needed

Water = 5/16 × 5/2 = 25/32 liters

Verification: Both methods give the same result: 5/16 hectare and 25/32 liters.

Extension Problem

Resource Planning

If you have 3 liters of water available, is it enough for the grass area? If not, how much more water do you need?

Step 1: Convert 3 liters to fraction

3 liters = 3/1 = 96/32 liters

Step 2: Compare with needed water

Needed: 25/32 liters
Available: 96/32 liters
Since 96/32 > 25/32, you have enough water!

Step 3: Calculate excess water

Excess = 96/32 - 25/32 = 71/32 = 2 7/32 liters

Answer: Yes, 3 liters is enough. You'll have 2 7/32 liters left over.

Practice Problems

Problem 1

A rectangular field is 2½ km long and 1⅓ km wide. What is the area of the field? If you need ¾ kg of seeds per square kilometer, how many kg of seeds do you need?

Your solution:

Problem 2

A recipe calls for 1⅔ cups of flour. You want to make 2½ times the recipe. How much flour do you need? If flour costs $2.40 per cup, what's the total cost?

Your solution: