Total quantity of juice Li had = 5 2/3 gallons.
In breakfast used quantity = 2 3/4 gallons.
Number of gallons of juice does Li have left = Total quantity - used quantity.
Therefor, number of gallons of juice does Li have left = 5 2/3 gallons - 2 3/4 gallons.
Let us convert those mixed fractions into improper fracions first.
5 2/3 = (5*3+2)/3 = 17/3.
2 3/4 = (2*4+3)/4 = 11/4.
5 2/3 gallons - 2 3/4 gallons = 17/3 -11/4.
Subtracting fractions by taking common denominator (lcd).
We have common denominator of 3 and 4 = 3*4 = 12.
So, 17/3 -11/4 = 17*4/3*4 - 11*3/4*3
= 68/12 - 33/12.
= (68-33)/12.
= 35/12
Let us convert 35/12 into mixed fraction now.
Dividing 35 by 12 we get quotient 2 and remainder 11.
So, 35/12 can be wriiten in mixed fractions as 2 11/12.
And final answer would be, Li have left 2 11/12 gallons.