Thus, the calculator-abacus was invented. In Chinese history, the origin of the abacus can be traced back to the Spring and Autumn Period, 600 B.C., and it was widely used before the invention of Arabic numerals appeared in the world. The abacus has proven to be one of ancient Chinaâs greatest inventions. Before the abacus was invented, people used small wooden sticks as calculation chips to make calculations. (Image: Derrick Coetzee via Flickr/ CC0 1.0))
Social anxiety disorder, also called social phobia, is an anxiety disorder in which a person has an excessive and unreasonable fear of social situations. Anxiety (intense nervousness) and self-consciousness arise from a fear of being closely watched, judged, and criticized by others.
Symptoms of social anxiety disorder can include: 1  Intense anxiety in social situations. 2  Avoidance of social situations.  Physical symptoms of anxiety, including confusion, pounding heart, sweating, shaking, blushing, muscle tension, upset stomach, and diarrhea.