Answer
a. $5$
b. $2$
c. $4$
d. $3$
e. $1$
f. $4$
Work Step by Step
a.
$f(g(1))=f(6)=5$
b.
$g(f(1))=g(3)=2$
c.
$f(f(1))=f(3)=4$
d.
$g(g(1))=g(6)=3$
e.
$(g\circ f)(3)=g(f(3))=g(4)=1$
f.
$(f\circ g)(6)=f(g(6))=f(3)=4$