As the country grew, each census required greater effort than the last. That problem led to the invention of the punched card – and the birth of an industry.
An employee creates punch cards using information from a filled in 1950 Census Population Form.
U.S. Census Bureau
A través de juegos y tareas domésticas, los padres pueden enseñar a sus hijos habilidades básicas de matemáticas, como contar, algo de geometría y pensamiento algebraico.
Getting ready for school.
Studio.g photography/shutterstock