[STRIKE]A[/STRIKE] "The mystery of calculus depends on an understanding of algebra."
Why is it not "understand of algebra"?
Welcome to the forum. :hi:
Please note my corrections above. Also, I have changed your thread title. Titles should be unique and relevant to the thread, and should include some/all of the words/phrases you are asking us about.
We use "understanding" because we need a
noun after "depends on an ...". "Understand" is only a
verb.
Please tell us where you found the original sentence and who wrote it. That is a requirement here every time you quote someone else's words.