When you are doing arithmetic by hand because your calculator’s batteries just gave up and your laptop is in the other room, it’s best if you can check your calculations with a different process than ...

IIIF provides researchers rich metadata and media viewing options for comparison of works across cultural heritage collections. Visit the IIIF page to learn more. This illustrated pamphlet describes ...

A thorough understanding of addition and subtraction requires knowledge of the inverse relation between these operations. According to Piaget (1952), any inverse relation poses a significant challenge ...