change their denominator by using the LCD Method
example: 1 3/4 and 1/3 = their LCD is 12
divide their LCD with its denominator
example: 12/4=3 12/3=4
if it has a whole number multiply it to the quotient
example: 3*1=3
then add it to the numerator
example: 3+3=6 4+1=5
so their numerator is both 6
if you got the two fractions
-subtract the numerator and then copy their denominator
example: 1 6/12 - 5/12= 1 1/12
