Ideal Arithmetic Tube For Teaching Addition & Subtraction Math Manipulative

From the 1970's. Shows discoloration on the cards. The cards can be used for addition and subtraction. And the answers are on the back. This item is missing the little balls that are used for a visuals that go in the little Kasper on the right side. I'm sure you could purchasea little balls to lineup along the side. I wish I had them, but they were missing from my grandmother's collection. This was found in her teaching closet. She was a math specialist.