The fraction may be simplified when the numerator and denominator have a common factor greater than one. Units are often referred to as ones. Eg, 4∙2 has 4 units and 2 tenths, or you could say 4∙2 has ...
Subtract the integers and subtract the fractions. When the fraction to be subtracted is bigger than the first fraction, change the mixed numbers to improper fractions first then do the subtraction.