Question

How can I solve this problem 2 1/2*4 1/5

Answer 1

Well first you would turn the two into improper fractions.
2 and 1/2 would be 5/2, and 4 and 1/5 would be 21/5
then you mulitply.

5              21              105                                    
_               _        =      __    then simplify  =   10 and 1/2 .

2               5                10

Answer 2

The easiest way to solve this problem is to make the fractions improper. 2 1/2 would be 5/2 and 4 1/5 would be 21/5. 
Then you would multiply them straight across.
5*21= 105
2*5= 10
Afterward you would simplify.
105/10=10 1/2