Answer
a) $h(g(0))=-1$
b) $g(f(4))=-1$
c) $h(h(0))=0$
d) $g(h(f(4)))=0$
e) $f(f(f(1)))=0$
f) $h(h(h(0)))=-1$
g) $f(h(g(2)))=1$
h) $g(f(h(4)))=-1$
i) $g(g(g(1)))=4$
j) $f(f(h(3)))=0$
Work Step by Step
a) $h(g(0))=h(0)=-1$
b) $g(f(4))=g(-1)=-1$
c) $h(h(0))=h(-1)=0$
d) $g(h(f(4)))=g(h(-1))=g(0)=0$
e) $f(f(f(1)))=f(f(0))=f(1)=0$
f) $h(h(h(0)))=h(h(-1))=h(0)=-1$
g) $f(h(g(2)))=f(h(3))=f(0)=1$
h) $g(f(h(4)))=g(f(4))=g(-1)=-1$
i) $g(g(g(1)))=g(g(2))=g(3)=4$
j) $f(f(h(3)))=f(f(0))=f(1)=0$