Answer:
It uses repetition to show there were six hundred men.
Step-by-step explanation:
Repetition is repeating words, lines, or stanzas and it is used to emphasize a feeling or idea, create rhythm, and/or develop a sense of urgency.
The first stanza, "HALF a league, half a league" is used to emphasize the fact that there were six hundred men , to develop the idea of the remaining stanzas.