Rare addition tool / kids calculator- a rare, quaint educational device that's charming in its simplicity!

Vintage "Math O Matic Arithmetic Tutor" by Peter & Paul Co. (Sant Fe Springs, CA)

2 rows of sliders allow you to add 1+1 all the way to 10+10 and everything in between
Hard plastic construction in die cut window cardboard box
Box measures 3.75" x 8.25"
Note: the mascot character on the box implies addition, subtraction and multiplication- THIS TOY ONLY DOES ADDITION
Patented device, long defunct company
CONDITION: Good, pre-owned and well maintained vintage condition; no cracks, chips/ box has a stray mark on the front and some light surface & edge wear