Overlapping Region

Hello, children!

Let's do some revision on overlapping regions (area) with a virtual geoboard.

Example:
The figure below is made up of 2 squares of different lengths. What fraction of the whole figure is Part C?




Observe & understand...

1. There are 2 squares in this figure.
2. Part of the smaller square overlaps with the larger square i.e. Part C
3. The entire figure is formed with 3 parts, namely A, B & C.

Think...
How can we find the total no. of units that the entire figure has?

1. Count the total no. of big parts that form the entire figure. (3 parts, namely A, B & C.)
2. Find the no. of units for each of the big parts.
3. Entire figure = Part A + Part B + Part C

Common mistake:
Entire figure = Square 1 + Square 2

Why is this incorrect?