Finding Area by Covering Rectangles with Square Units
Objective
Students will calculate the area of rectangles by counting square units and applying the length times width formula.
Materials
- Grid paper
- Rulers
- Colored pencils
- Chart paper
- Scissors
Hook
Show students two different rectangles drawn on the board and ask pairs to predict which one takes up more space. Have them discuss their reasoning with their partner before sharing predictions.
Main Activity
Students work in pairs to measure and find the area of various rectangles drawn on grid paper. First, they count individual square units by coloring them in, recording their totals. Next, they measure the length and width of each rectangle using rulers, then multiply to find the area using the formula. Partners compare their counting method results with their multiplication results to verify accuracy. Each pair creates a poster showing one rectangle with both methods clearly labeled, then presents their findings to another pair.
Discussion Questions
- How did counting squares compare to using the length times width formula?
- What happens to the area when you double the length of a rectangle?
- How would you find the area of an L-shaped figure made of rectangles?
- Why do we measure area in square units instead of regular units?
- When might someone need to calculate area in real life?
Exit Ticket
Draw a rectangle that is 4 units long and 3 units wide, then calculate its area using multiplication.
Differentiation
Support: Provide rectangles with smaller dimensions and encourage students to count squares first before attempting the formula.
Extension: Challenge students to find the area of compound shapes made of two or more rectangles joined together.
