When using fraction strips, how do you know that two fractions are not equivalent?

If the stripes are not lined up equally then they are not equivalent. 

hope this helps :D

Well, line them up and make sure they end the same. Then, see if they meet the same point. If it's something like 32/100 and 23/50, it might be best to use a ruler. Also, the slightest bit of aprt will mean they aren't equivalent

Just tell koda to adjust the number of shapes himself.