The phrase "great number" refers to a large quantity or a lot of something. It means there is a significant amount or a large group of things or people. Full definition
There's really no evidence to support an expectation of greater numbers of more intense tornadoes over a larger geographical range in the course of longer tornado seasons. (realclimate.org)
For white students of similar backgrounds, the «penalty» for attending a school with greater numbers of black students disappeared. (hechingerreport.org)