Started by setting out a couple of addition flash cards and the child to make the addition problem with the cubes. Show child that they can self check with the answers on the back. Can also use with Legos!
I could totally do this with money-- dollars on a pumpkin then popsicle sticks with bills and coins that add up to the amount. Addition/subtraction sorting - child needs to determine which sticks add up to the number on the bucket.
I love this Geometric Shapes chart shared by Kathryn on Kindergarten Kindergarten! I had to scroll down to find it, but found a ton of great ideas along the way. I also loved her shape museum. (She has lots of free ideas for teaching math concepts.