Multiplying fractions are actually pretty easy :)
I see you have a mixed number, so convert that to an improper fraction:
1*4=4, 4+3=7. So the improper fraction would be 7/4.
To do 5*7/4, display 5 as a fraction by putting it over 1.
5/1 * 7/4
Multiply numbers and denominators across
5*7=35
1*4=4
35/4 would be your answer, or in whole number form it would be 8 3/4:)