Kid President - How To Change The World with Kindness. Teaching kindness to children is part of the fourth National Health Education Standards: Students will demonstrate the ability to use interpersonal communications skills to enhance health and avoid or reduce health risks. Learning to be kind helps build a positive learning environment.
The stone-throwers took two forms-either like the arrow-firing apparatus or large one-armed catapults, known in the 4th century CE as the onager or 'Wild Ass' because of its terrific recoil but, in fact, first appearing in the 2nd century CE.
Best Answer: The first abacus has been dated to the sixth century BC and about 200 years after it was used by the Chinese, the abacus caught on in several Mediterranean civilizations. But it is quite a controversial matter. The first record of the abacus was from a sketch of one in a book from the Chinese Yuan Dynasty (14th Century). If the abacus was invented by the Chinese in the sixth century BC then there is no definite answer to the question since the first official whole Chinese dynasty was the Qin Dynasty in 221 BC. This website has a fascinating account of the history of the abacus and other counting devices.