Subject: Grapsing the size of an average human cell

I need to give a talk in which I help kids visualize the size of an "average" 
human cell, which I have found via research to be about 20 microns in diameter, 
or 1/200ths of a millimeter. But all these measurements are too abstract to 
kids and I want them to at least attempt to get a visceral feel for these 
scales. Need to get this into inches, not metrics. Since a millimeter is 
roughly 1/25th of an inch, am I correct in having them do the following 
exercise, which can't be done but which the attempt to do should impress upon 
them the scale we are talking about: Plot out one inch on graph paper. Try to 
divide that inch into 25 equal smaller units (one of those units gets them to a 
millimeter). Then attempt to divide one of those smaller segments into 200 
smaller units (one of those still smaller units gets them to a 
micron/micrometer). An "average" human cell would fit into one of those 200 
smaller units. (20 microns = 1/200ths of 1/25th of an inch)? Is this 
interpretation of the math correct? Appreciate any help!

Re: Grapsing the size of an average human cell