Chinese Abacus. The abacus is first known in China from the Northern Song dynasty through the work of Shao Yong (1011-1077). Like many early inventions it is not clear precisely where it originally came from. Some say Central Asia; some Asia Minor and others China.
Snag(noun) a stump or base of a branch that has been lopped off; a short branch, or a sharp or rough branch; a knot; a protuberance. Snag(noun) a tooth projecting beyond the rest; contemptuously, a broken or decayed tooth.
It is from dialectal British snark, meaning 'to nag, find fault with', which is probably the same word as snark, snork, meaning 'to snort, snore'. (The likely connection is the derisive snorting sound of someone who is always finding fault.) Most dictionaries label snarky as Chiefly British Slang..