Subtracting values between two dictionaries/ floating point numbers

[snippsat]

how to #1 have these floating point numbers be not so large

Use string formatting,f-string Python 3.6-->.

>>> d = {'Quartz': 0.06999999999999984, 'Hydrogen': 0.040000000000000036, 'Iodine': 0.02999999999999997, 'Aluminum': 0.050000000000000044}
>>> print(f'Value of Quartz is {d["Quartz"]:.2f}')
Value of Quartz is 0.07

#2 how to then print out the item in the dictionary that holds the largest number

>>> d = {'Quartz': 0.06999999999999984, 'Hydrogen': 0.040000000000000036, 'Iodine': 0.02999999999999997, 'Aluminum': 0.050000000000000044}
>>> max(d, key=d.get)
'Quartz'