It's late so I'll make this short and sweet: I stole this idea from education.com and loved it so much I had to do it for myself. I modified them a little bit because my son is in kindergarten and doesn't really get the idea behind the "teens".
To get started you'll need Popsicle sticks, pens and/or number stickers and rubber-bands or duct tape.
Number your sticks 0-9 and count out 10 sticks, rubber band or tape together and label 10.
Write + and - and = signs on three more--adding higher math symbols as appropriate for your student.
Shove sticks in ziplock bag or box with label on it.
The bag may be less durable,
but it will fit in your purse easily and make math practice in the waiting room at the doctors office much easier.
Show to your kids and have fun!