Is she has 60 and half was used that would be 30 minus 3/8 and 3/8 is 0.375 which if u subtract 60-30-0.375 it would be 29.625 I’m pretty sure! Sorry if this didn’t help
So if you have 192 marbles and you want to group them in groups of 15 marbles each you would see how many times 15's there are in 192 or how many 192's would go into 15
