An approach to learning

There's been a recent question about this phrase on the Help Me! forums. At first glance it looks strange: when you see "an approach to…." you imagine that there should be the rest of the infinitive verb, as in "an approach to get…" or "an approach to find…" But the "to" in the phrase isn't part of an infinitive verb, but a preposition, and after prepositions we need a gerund:

"An approach to learning…"
"I look forward to seeing you soon."

Other prepositions:
"A way of getting results…"
"By doing this you find…"
"These scissors are for cutting material."
"From working with these students she understood…"