# I need help checking an expression

I have edited this great activity for a course I am teaching. On slides 6 and 7 the students input an expression to correct an error the machine makes. I have a working check on slide 6, but it won’t work on slide 7. Can someone help me with slide 7? Thanks so much.

011-38 Formulas

Maybe try rounding the key functions?

I would use pattern matching, here. Something like this:

p= patterns