| Ibn al‐Majdī | |
| Birth Date: | 1359 |
| Birth Place: | Cairo, Mamluk Sultanate, now Egypt |
| Death Date: | 27 January 1447 (aged 88) |
| Death Place: | Cairo, Mamluk Sultanate, now Egypt |
| Occupation: | Astronomer, mathematician, engineer, grammarian, faqih, calenders |
| Era: | Mamluk era (Islamic Golden Age) |
Ahmad bin Rajab bin Taibugha al-Majdī al-ala’i bin Abdullah Shihāb al‐Dīn Abu al-Abbas (; 1359–1447 CE) was an Egyptian mathematician and astronomer. His most important mathematical work was "Book of Substance", a voluminous commentary on the Summary of the Operations of Calculations by Ibn al-Banna'.[1]