Squares that play well together
 

The following are sizes that are compatible in piecing:
2, 3 1/2, 5, 6 1/2, 9 1/2
Two 2's make a 3 1/2, three make a 5; two 3 1/2's make a 6 1/2, three make a 9 1/2; two 5's make a 9 1/2.
OR
2 1/2, 4 1/2, 6 1/2, 8 1/2, . . . (Combinations are more obvious.)
OR
3, 5 1/2, 8, 10 1/2
Two 3's make a 5 1/2, three make an 8, four make a 10 1/2; two 5 1/2's make a 10 1/2; a 5 1/2 plus a pair of 3's makes an 8 in one direction only.

Thank you for this information. This will make it easier for me.

thanks for the information. I copied it down.

thanks for putting it all on paper retired math teacher!

Yes, I also thank you for taking the trouble to compile and post this. I cut and pasted it into a document and printed it. I'll keep it by my sewing machine. Excellent info!!

I make a lot of donation quilts & this will make cutting up my stash so much easier. Thank you SO MUCH!!! Math is not my forte but I'm glad it is yours. K

thank you, I also make donation qults and it helps when cutting u scraps, I never gave it a thought, but now that I know, it is a good thing to pay atention to.

Thank you so much for your time to do this. I just printed it out to keep close at hand.

Thanks so much! I printed it an am posting it at our Church quilting room.

Very helpful