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Jade mirror of the four unknowns

study of mathematics and algebra in ancient China, compiled by Zhu, Shijie in 1303

Pronunciation
/ʤeɪd ˈmɪrə əv ðɪ fɔː ʌnˈnəʊnz/
/ʤeɪd ˈmɪrər əv ðə fɔr əˈnoʊnz/