( ( Calculate ( the ( percentage composition ) ) ) ( by ( mass ( . ( 9 . ) ) ) ) )
(ROOT (S (VP (VB Calculate) (NP (DT the) (NN percentage) (NN composition)) (PP (IN by) (FRAG (NP (NN mass)) (. .) (NP (CD 9)) (. .))))))
Calculate the percentage composition by mass. 9.
(ROOT (S (NP (DT The) (NN term) (NN percent) (NN composition)) (VP (VBZ means) (NP (DT the) (NN percentage)) (PP (IN by) (NP (NP (NN mass)) (PP (IN of) (NP (NP (DT each) (NN element)) (PP (IN in) (NP (DT a) (NN compound)))))))) (. .)))