Tweet  Share 
How did you use this starter? Can you suggest
how teachers could present or develop this resource? Do you have any comments? It is always useful to receive
feedback and helps make this free resource even more useful for Maths teachers anywhere in the world.
Click here to enter your comments.
If you don't have the time to provide feedback we'd really appreciate it if you could give this page a score! We are constantly improving and adding to these starters so it would be really helpful to know which ones are most useful. Simply click on a button below:
Previous Day  This starter is for 16 November  Next Day
Click the button below to show the answer.
1
2
3
4
5
6
7
8
9
10
11
12
One possible method of systematically counting the rectangles it to start by looking at all of the points that could be the top left corner of a rectangle. These have been numbered working from top left to bottom right.
Now take each of these 'corners' in turn and count how many rectangles can be found containing this corner at the top left. The results are shown in the table below:
Corner  Number of rectangles  View rectangles 
1  1  
2  3  
3  2  
4  3  
5  1  
6  5  
7  3  
8  2  
9  2  
10  2  
11  1  
12  1  
Total:  26 
Your access to the majority of the Transum resources continues to be free but you can help support the continued growth of the website by doing your Amazon shopping using the links on this page. Below is an Amazon search box and some items chosen and recommended by Transum Mathematics to get you started.
Teacher, do your students have
access to computers? 

Here a concise URL for a version of this page without the comments.
Transum.org/go/?Start=November16
Here is the URL which will take them to another systematic listing activity.
Other shape counting starters:
How Many Squares 1?
 How Many Squares 2?
How Many Triangles 1?

How Many Triangles 2?  How Many Triangles 3?
How Many Rectangles?
 Rectangles Investigation 
Icosahedron