The Game of the Button Bag
From your button bag select a number of different buttons, two of each kind. Let the child sort out the pairs and thus become somewhat familiar with the sizes and shapes. Then mix the buttons, blindfold the child, and let him match the pairs entirely by feeling. Have him lay them out in pairs as he matches them. Then take off the blindfold and let him see them just as he has matched them, and count for himself how many are right and how many wrong.