In order to combine fractions, they need to have the same denominator.
To figure out what value to make the denominator, find the least common denominator of 4 and 5:
4: 4, 8, 12, 16, 20
5: 5, 10, 15, 20
The LCD is 20, so multiply 4/5 by 4/4 and -1/4 by 5/5 to make the denominator = 20
[tex](\frac{4}{4} )\frac{4}{5} -(\frac{5}{5} )\frac{1}{4} =[/tex]
[tex]\frac{16}{20} -\frac{5}{20} =[/tex] Now combine the fractions
[tex]\frac{16}{20}- \frac{5}{20} =\frac{11}{20}[/tex]
