In this Grade 7 Saxon Math Course 2 lesson, students learn how to estimate the area of irregular shapes by tracing their outlines onto a square grid, counting whole squares and half squares to approximate total area. The lesson applies this grid-counting method to real-world problems, such as calculating pounds per square inch by dividing weight by the estimated contact area of a shoe print or circular castor.
Section 1
📘 Estimating Areas
To estimate the area of an irregular shape, overlay it on a grid. Count the number of full squares and then combine partial squares to approximate the total area.
This is a foundational skill. Next, you'll practice by applying this estimation method to various shapes in worked examples and hands-on activities.
Section 2
Estimating area on a grid
To estimate the area of an irregular shape on a grid, count the complete or nearly complete squares as whole squares. Then, count the squares that are about half within the outline and treat every two as one whole square.
Got a wacky shape like a puddle or a handprint? Just slap a grid on it! This cool method turns a tricky problem into a simple counting game. You count up all the full squares inside the shape, and then you pair up the 'halfway' squares along the edge. It's a super clever way to measure wiggly things accurately!
Section 3
Estimate with whole and half squares
The estimation method involves two steps: first, count all squares that are fully or almost fully inside the shape. Second, count all squares that are about half inside the shape, divide this count by two, and add it to your first number.
Don't let those pesky edge pieces confuse you! Just think like a puzzle master. Your first job is to collect all the 'full' pieces inside your shape. Then, look at the edge pieces and find the ones that are about half-in, half-out. Pair them up, since two halves make a whole, and add them to your collection for a great area estimate.
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Section 1
📘 Estimating Areas
To estimate the area of an irregular shape, overlay it on a grid. Count the number of full squares and then combine partial squares to approximate the total area.
This is a foundational skill. Next, you'll practice by applying this estimation method to various shapes in worked examples and hands-on activities.
Section 2
Estimating area on a grid
To estimate the area of an irregular shape on a grid, count the complete or nearly complete squares as whole squares. Then, count the squares that are about half within the outline and treat every two as one whole square.
Got a wacky shape like a puddle or a handprint? Just slap a grid on it! This cool method turns a tricky problem into a simple counting game. You count up all the full squares inside the shape, and then you pair up the 'halfway' squares along the edge. It's a super clever way to measure wiggly things accurately!
Section 3
Estimate with whole and half squares
The estimation method involves two steps: first, count all squares that are fully or almost fully inside the shape. Second, count all squares that are about half inside the shape, divide this count by two, and add it to your first number.
Don't let those pesky edge pieces confuse you! Just think like a puzzle master. Your first job is to collect all the 'full' pieces inside your shape. Then, look at the edge pieces and find the ones that are about half-in, half-out. Pair them up, since two halves make a whole, and add them to your collection for a great area estimate.
Book overview
Jump across lessons in the current chapter without opening the full course modal.
Continue this chapter