How many fifths are there in four wholes?

To determine the number of 1/5 there are in 4, divide the 4 by 1/5.
4 -: 1/5
To divide them, express the 4 as a fraction.
=4/1 -: 1/5
To divide two fractions, flip the second fraction and change the operation from division to multiplication.
=4/1 xx 5/1
=20/1
=20
 
Therefore, there are 20 fifths in four wholes.