You can compare ratios by using a colen, the word "to", and a fraction. Examples
3:4
3 to 4
3/4
you find what they both divide by and then divide each one and then you keep doing that until you cant no more
Answer:
feldspar, because it has a higher number then gypsum and apatite, and it can be scratched by quartz because it has a lower number.
