Students can work cooperatively in centers or independently with this great resource for number recognition. This product provides three versions of numbers 1-20 as puzzle pieces.
Students create a complete rectangle to know they have completed a puzzle. I have also provided an answer key with the completed puzzles on a single document for students to check their work.
Laminate for longterm use.
For prep, I recommend cutting out the rectangles with a cutting block, then cutting the pieces individually.
Each number has different objects on the card, so while working with the student the teacher could build background knowledge on those objects.