Srimad Bhagavatam 10.45.33 says: “That best of brahmanas, the spiritual master Sandipani, was satisfied with Their submissive behavior, and thus he taught Them the entire Vedas, together with their six corollaries and the Upanisads.” Srimad Bhagavatam 10.45.35-36 says: “O King, those best of persons, Krsna and Balarama, being Themselves the original promulgators of all varieties of knowledge, could immediately assimilate each and every subject after hearing it explained just once. Thus with fixed concentration They learned the sixty-four arts and skills in as many days and nights. Thereafter, O King, They satisfied Their spiritual master by offering him guru-daksina.” Part of the purport reads: “The following list comprises the sixty-four subjects mastered by Lord Krsna and Lord Balarama in sixty-four days. Additional information may be found in Srila Prabhupada’s ‘Krsna, the Supreme Personality of Godhead’: (51) yantra-matrka, composing magic squares, arrangements of numbers adding up to the same total in all directions.