How do u do this stuff i’m confused

Ok so I'll show u how to do number 7
So 12 and one third basically equals 12+(1/3)
Now in order to add this to another fraction, we need to make the mixed numbers in improper fractions
So 12 and (1/3)=(36/3)+(1/3)
And 9 and (2/3)=(27/3)+(2/3)
Ok so the first number (or 12 and (1/3)) basically equals (37/3)
The second number (or 9 and (2/3)) equals (29/3)

Now that we have the two numbers with common denominators, we can do the math.

(37/3)-(29/3) is the same as (37-29)/3
So simplifying would be
(8/3) or 2 and (2/3)
Hoped this helped