I have yet to read a math book that mentions ancient African mathematicians at any length or level of detail. There is scant coverage in academic settings in the United States, perhaps elsewhere too. Most books have side notes that mention only European and east Asian mathematicians.
Obviously, the ancient Egyptians had a lot of knowledge about trigonometry, given that they built the pyramids.
Well-regarded ancient Greek intellectuals acknowledged the achievements of African mathematicians throughout their historic writings. Modern academicians consider these ancient Greek and Roman authors to be credible, yet that credibility is selective regarding African mathematicians. For specific examples, please see this link.