Ten Thousand
numeral
When you have one ten thousand you just have ten thousand. In Japanese, though, you specify how many ten thousands you have, though (which is weird in English, but should make sense if you think about it).
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.
一万ポンド
ten thousand pounds
一万円
ten thousand yen
一万ドル
ten thousand dollars
ここの人口はおよそ一万人です。
The population here is about 10,000.
この中古のコートは一万円でした。
This secondhand coat was 10,000 yen.
一万メートルは十キロメートルです。
10,000 meters is ten kilometers.