I hope this one doesn't stump you!

I am working with a spreadsheet that has a single field that lists codes for employees working on a given task. For example,
Task A 443A, 5133, SQE
Task B 22A, POP, 4355
Task C 5145, 234, 5124, 513F
etc etc

I want to identify how many times there is a "51xx" code, where x is numeric only -- Task A would have 1, Task B would have 0 and Task C would have 2.

Is there some way to do this using a standard Excel function?

Many thanks.