Difference means subtract, so we use subtraction:
*first we need to make the fractions have the same denominator
1/4 = 3/12
2/3 = 8/12
126(3/12) - 78(8/12)
*since the fraction in the first term is smaller than the second, make it improper
125(15/12) - 78(8/12)
now simply subtract:
125 - 78 
= 47
15 - 8 
= 7
* this is now (7/12)
now put them back together:
47(7/12) 
That's the final answer!
        
             
        
        
        
Answer:
   Probability that she or he bought lunch in the cafeteria and chose pizza as an entree = 12/100 =0.12 = 12%
Explanation:
   Let number of students be 100.
   At Taylor Street School, 40% of the students bought lunch in the cafeteria today
  Number of students bought lunch = 100 x 40/100 = 40
  Of the students who bought lunch in the cafeteria today, 30% chose pizza as their entree
  Number of students bought pizza = 40 x 30/100 = 12.
  Probability of an outcome = Number of favorable outcome/ Total number of outcome 
  Probability that she or he bought lunch in the cafeteria and chose pizza as an entree = Number of students bought pizza/Total number of students 
         = 12/100 =0.12 = 12%
   Probability that she or he bought lunch in the cafeteria and chose pizza as an entree = 12/100 =0.12 = 12%