One Big Triangle

Here are nine triangles.  Each one has three numbers on it.

 

Your challenge is to arrange these triangles to make one big triangle, so the numbers that touch add up to 10.

Let us know how you go about trying to make the big triangle.
How did you get started?
What did you do next?

You can print out this copy of the triangles and cut them out, then try arranging them.  
If you prefer, here is a printable version of the triangles with the numbers represented on tens frames.

Alternatively, you might like to use this interactivity, which allows you to drag each triangle onto the large triangle.