The Chinese abacus is thought to have been created by a famous mathematician Cheng Dawei of the Ming Dynasty between 1368 and 1644. A typical elementary abacus has 10 parallel wires strung between two boards on a frame, with nine beads on each wire. Each bead has a value of 10, a multiple or sub multiple of 10.
The definition of a snigger is a contained or half held-in laugh. An example of a snigger is a quiet laugh behind a person's back. Snigger is defined as to snicker or hold back a laugh. An example of snigger is to secretly laugh at someone behind their back.
Schizoaffective disorder (abbreviated as SZA or SAD) is a mental disorder characterized by abnormal thought processes and deregulated emotions.