Need help with NaN error and/or field do not match
I am trying to add two formulas to my pdf form:

The first formula is for BMI which is 703*weight in pounds/height inches squared. I made the BMI box a number initially but an error came up that said fields don't match. I Imagine it is either because it is a long decimal or because there is a zero in the denominator until someone types a value in there. I changed the field to reflect "none" in formatting and now it is showing "NaN" until something is typed. I would like for "NaN" not to show.
I have ZERO knowledge of javascript, and just need to know what to type in and where. I figure the solution to the first formula will help me solve the second formula issue.
