While it might take time, before putting a puzzle out for student use you might number each puzzle and then write on the back of each puzzle piece the number of that puzzle. (educationworld.com)
Cut the sleeve along the adjustment line and overlay the two pieces the number of cm / inches needed. (feedspot.com)
I would have to say this two piece number makes my heart pitter and patter every time look at it. (thejpetite.com)