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Johannes Kepler (1571-1630)

Born in Germany.
He published one one the first works to consider infinitesimals, a concept which led to the formulation of the differential calculus.
Mohammed ibn Mûsâ al-Khowârizmî (fl. ca. 825 CE)

Born in Iraq.
He provided solutions of linear equations and quadratic ones.
Abu Mahmud Hamid ibn Al-Khidr al-Khujandi (940-1000 CE)

Born in Tajikistan.
He may have discovered a sine theorem relative to spherical triangles.
He proved that the sum of two cubic numbers cannot be a cubic number.
He wrote a text on obliquity of the elliptic, including the measurements of it.
Seki Kowa (1642-1708)

Born in Japan.
He independently discovered many of the mathematical innovations of the West.
He was able to popularize mathematics in Japan.
E. E. Kummer (1810-1893)

Born in Germany.
He established that the proposition that a number can be resolved into the product of powers of primes in only one way is not true of every complex number.
He wrote on the transformations of hypergeometric functions.