Like the Binary Towers, the Binary Cards introduce children to the binary number system, which is the fundamental system on which computers are built. Instead of balls, quantities are represented with etched dots that children can touch. The string of zeros and ones on the bottom displays the binary number for the corresponding number of dots. Through flipping the cards back and forth and counting the dots, children gain a deeper understanding of place value in the binary number system, and can easily convert decimal values into binary numbers.