Big numbers stack a multiplier onto ひゃく (100) or せん (1000).
JLPTN5
[number] + ひゃく / せん
にひゃく is 200, ごせん is 5000 — multiplier + ひゃく/せん, with tens and ones riding along after (ひゃくじゅうなな = 117). A few combinations shift sound (さんびゃく, ろっぴゃく, はっぴゃく; さんぜん, はっせん).
Tips and Common Traps
Maru· Common trap
A hundred is ひゃく and a thousand せん, with no いち in front. Ten thousand is いちまん, where いち stays.
hanamaru
