\textbf{[Solution]}  $$18 + 9 + 6 = 23$$ 
Amy has $$18$$ boxes of clay.  Bala has $$9$$ boxes of clay.  Cindy has $$6$$ boxes of clay.  How many boxes of clay do they have altogether? 
A) $$35$$ 
B) $$32$$ 
C) $$33$$ 
D) $$34$$ 