What was the significance of child labor in Egypt, Mesopotamia, Sparta?

In ancient states like Egypt, Sparta, child labor was common, but only among slaves. Children of slaves did almost the same work as adults, some were entrusted with cleaning, sewing, grazing animals, and harvesting. Children made a great contribution to the development of civilization, doing work that adults were not suitable for. In the rich inhabitants of Egypt, children did not work, they were trained in various subjects: shooting, fencing, literacy. All children worked in Sparta, even the children of the tsars and the council, they were brought up strong from birth.