He attended primary school in Kiev, then spent a year at a private school before entering the Kiev School of Commerce. After several talks, Grave was convinced of his remarkable abilities and accepted him in his seminar as a full and equal participant. For three years Ostrowski participated in Grave 's seminar while completing his course at the School of Commerce. Ostrowski had not been a mere observer in Grave 's seminar during these years, however, for by the time he completed his studies at the College of Commerce he had already found original results on Galois fields and had written his first paper with Grave 's assistance. It would seem natural that this extraordinarily well qualified student would be more than welcome to begin his formal studies of mathematics at Kiev.
Few student can begin their studies having already written a mathematical paper.
Life is often not that simple, however, for Ostrowski had graduated from the College of Commerce and not from a high school. Grave pleaded with the educational trust to allow Ostrowski to study at university, even suggesting that he might be allowed to be an external student. Permission was not granted so Grave wrote to Landau and Hensel in Germany asking for their help. Both Landau and Hensel offered to help solve Ostrowski's problem and invited him to Germany. Ostrowski accepted Hensel 's offer of a place at the Marburg University and in 1912 he began his studies there under Hensel 's supervision.