Adjectives and their opposites

In German, many adjectives have an opposite form when used to express the opposite meaning. For instance, "groß" (big) has the opposite form "klein" (small). In exercises for learning German adjectives, it is important to practice identifying these opposites to better express nuances and comparisons.

Question 1
dick -?
Question 2
voll - ?
Question 3
alt - ?
Question 4
hungrig - ?
Question 5
jung - ?
Question 6
schwach -
Question 7
billig -
Question 8
arm - ?
Question 9
warm - ?
Question 10
leicht -
Question 11
schlecht -
Question 12
kalt - ?
Question 13
heiß - ?
Question 14
traurig - ?
Question 15
krank -
Question 16
groß - ?
Question 17
schnell - ?
Question 18
kurz - ?