This is a promotion for the American citizens to invest their money into E war bonds. It tried to promote education on the war instead of schooling because that's how imperative and desperate the U.S was to get any sort of money. In World War I, the United States raised $21.5B in today's money from selling war bonds, and the Selective Service Act enforced mandatory enlistment of young adults aged 18 and older to help the war effort. This happened again in the 1940s, since we were involved in World War II. These temporary lapses in schooling created a dent in the progress of education because the nation was focusing people's attention on war efforts rather than schooling, and it is imperative that young kids get the schooling they need in order to be successful. We did, however, bounce back eventually and create a somewhat well-functioning education system in the 1960s.
This poster from 1919 shows people being educated and trained at different schools in New Jersey. They were being trained as machinists, blacksmiths, welders, automobile mechanics, tractor mechanics, and in small arms and machine guns, explosives, artillery mechanic, saddler, and woodworking. These were important jobs because the US was trying to provide for its army. So instead of going to regular college, kids were trained at a job provided by the military.
The 1900s-1950s had a primitive education system where there was not as much emphasis put on core classes such as math and science. Many kids started working as soon as they could, either by themselves or with a parent. The education system before the 1950s had a lot of room to grow, but there was much hope for positive development as even in 1920, American education was much greater than it had been thirty years prior.