multiplication

5 x 4 2/5 =   5x4 + 5 x 2/5 = 20 + 2 = 22

first, convert both fractions into improper fractions. for the 5 simply put a 1 as the denominator! and for 4 and 2/5 just multiply 4 by 5 and add two (now its 22/5) 

now we will need too find the lcd, which is 5

our new fractions are 25/5 and 22/5

multiply these two fractions too get your answer