Finding the Area of a Rectangle
Students will be able to find the area of a rectangle by counting tiles and multiplying.
- Tell your students that they will be learning how to find the area of a rectangle.
- Ask your students if they know what the word area means. Explain to your students that it is the space inside a shape.
Explicit Instruction/Teacher modeling(15 minutes)
- Instruct your students to gather on the floor.
- Place the blocks in a 4 x 5 format on the mat.
- Ask your students to tell you the area of the rectangle by counting the blocks.
- After that, ask your students if they can calculate the area of the rectangle using another method that is quicker.
- Explain to your students that they can multiply the number of the blocks in the row by the number of blocks in the column to get the answer.
- Ask your students to skip count by 4's 5 times to prove that multiplying the numbers will give them the same answer that they would get by counting the blocks.
- Repeat the above steps using different numbers.
Guided Practice(20 minutes)
- Instruct your students to draw the rectangles with the following sides: 4 by 2, 3 by 7, 9 by 4, 7 by 8, and 4 by 7.
- Instruct your students to first calculate the area by counting the squares inside the rectangle. After that, instruct your students to calculate the area by multiplying.
- Let your students know that each square represents one unit.
- Go over the answers with your students as a class.
Independent working time(15 minutes)
- Ask your students to complete the Finding Area: Level 1 worksheet.
- Ask your students to draw the squares inside each rectangle as well.
- Go over the worksheet as a class.
- Instruct your students to draw a building made out of rectangles on graph paper. Have them find the area of each rectangle in their building. Direct them to add the area of all rectangles to find the area of the entire building!
- Instruct your students to draw a rectangle using blocks. Instruct your students to count the number of blocks that they used to create the rectangle. Explain to your students that they can find the area by multiplying the horizontal and vertical sides as well. Have them multiply the sides to make them understand that the answer is the same that they got by counting.
- Allow students to use manipulatives, such as blocks, to provide a more concrete understanding of the area of the rectangles.
- Pass out graph paper to each student.
- Ask your students to draw 2 rectangles on the graph paper.
- Ask your students to calculate the area of their rectangle using counting and multiplication.
- Remind your students that each square represents 1 unit.
Review and closing(10 minutes)
- Create 12 index cards that have a rectangular object from the classroom listed on them.
- You can use desks, drawers, dry erase boards, books, and tissue boxes as examples of rectangular objects.
- Ask your students to get into groups of 2, and have each pair draw a card.
- Ask the pairs to measure the area of the object on their card. Instruct your students to use centimeters if they get a small object and inches if they get a large object.
- Set the timer to 5 minutes.
- Ask each student to discuss the area of his object with the class.