Do you mean what is four and one fifth in a decimal, or one fourth and one fifth in a decimal form? I'll give you either answer anyway: 4 1/5 = 4.2 1/4 = 0.75 and 1/5 = 0.2

0.2, pronounced 'zero point two' Sometimes just written .2, but the dot is less visible. It means two-tenths, which is equal to one-fifth. It can be computed using long division: 5 goes into 1 zero times. 5 goes into 10 two times w/ no remainder. Locate the decimal point & you're done.