Isaac Newton didn't work with anyone to discover calculus. He developed his own version of calculus, known as "fluxions," independently and simultaneously with Gottfried Wilhelm Leibniz, who developed his own version called "calculus of infinitesimals."

While they arrived at similar conclusions, their methods and notations differed. This led to a bitter priority dispute, which overshadowed their individual contributions for many years.

Therefore, it's crucial to note that Newton didn't collaborate with anyone on his calculus discoveries. He worked independently, and his work was developed alongside, but not in conjunction with, Leibniz's contributions.