In Spring 2020, the need for redesigning online assessments to preserve integrity became a priority to many educators. Many of us found methods to proctor examinations using Zoom and proctoring software. Such examinations pose their own issues. To reduce the technical difficulties and cost, many Zoom proctored examination sessions were shortened; to create summative assessments we supplemented the short proctored sessions with short unproctored sessions. In the aftermath of the pandemic, the method of creating a large volume of examination variants is helping us design mastery-based examinations. We review the mathematics behind choosing the size of question pools to improve integrity of the exam. Finally we provide LaTeX files for generating examination variants from the pools.