Here is a great addition to your math centers or tubs. You can use only the pieces that your students are working on currently, add them as you introduce them, or use all the pieces at once. Each number (1-20) is represented in 4 ways. Numerals, tally marks, base 10 blocks and place value. Students match the cards that belong in the same set. These can be used in a pocket chart, as a memory game, or even Go Fish. I'm sure you can think of many ways these might come in handy in your classroom.
I hope these resources are helpful in your classroom, and make your teaching... well...a little more ..."easy peasy!"