Parents in Bavaria, Baden-Württemberg, Hesse, North Rhine-Westphalia and Schleswig-Holstein were forced to find other arrangements for their children.
Thousands of teachers and social workers walked off the job to increase pressure on public employers for better pay and working conditions. There will also be demonstrations in Munich, Stuttgart, Kassel, Frankfurt and Düsseldorf later on Tuesday.
Begun in early May, the ongoing strikes were restarted after talks broke down last week.
Union negotiators have said then they are prepared to dig in for a long-term battle. They claim current wages for 220,000 educators across the country are unfair, and workers need better healthcare options to handle the strain of their jobs.