Copyright © University of Cambridge. All rights reserved.
'One Big Triangle' printed from http://nrich.maths.org/
Drag and drop these triangles so that the numbers that touch add up to $10$
Try to use all the small triangles and move them to fill in all the spaces in the big triangle.
Full screen version
If you can see this message Flash may not be working in your browser
Please see http://nrich.maths.org/techhelp/#flash to enable it.
You can also print out these triangles, cut them out and rearrange them to make the big triangle.