2D sorting shapes

https://www.ictgames.com/mobilePage/abacus/ If I had 3 beads what numbers could I make on an abacus? What if I had 6 beads?{...}

Launch: http://www.ictgames.com/abacusInteger.html Introduce an Abacus in the classroom show how to represent numbers in the teens on the abacus  {...}

Place a half a domino on the board. How many more do we need to make 10? Dominoes. Give each{...}