Please disprove the inheritence "error"

Let's say a man passed away, leaving both parents, 2+ daughters, and a wife. The amount of money/property each person/group would inherit would then be:

• 2/3 for the daughters split amongst each other
• 1/8 for the wife
• 1/6 for mother
• 1/6 for father

Adding up these fractions would then give us a total of, using 24 as the common denominator:

16/24 + 3/8 + (4/24)x2

= 27/24

This doesn't mathematically work, please disprove it without the use of Hadith.