English/Japanese Listening Training: Numbers

10: Ten / Jyuu, 十
100: Hundred / Hyaku, 百
1,000: Thousand / Sen, 千
10,000: Ten thousand / Man, 万
1,000,000: Million / Hyaku-man, 百万
10,000,000: 10 million / Sen-man, 千万
100,000,000: Hundred million / Oku, 億
1,000,000,000: Billion / 10 Oku, 十億
10 billion / Hyaku-oku, 百億
Trillion / Icchou, 一兆
Ten trillion / Jyuccho, 十兆

1: One / Ichi, 一
2: Two / Ni, 二
3: Three / San, 三
4: Four / Yon, 四
5: Five / Go, 五
6: Six / Roku, 六
7: Seven / Nana (or Shichi), 七
8: Eight / Hachi, 八
9: Nine / Kyuu, 九
10: Ten / Jyuu, 十

Nana vs Shichi
I use Nana more frequently as Nana is easier to pronounce. I only use Shichi to talk about time, like It's Shichi-ji (7 o'clock) now" or "It's Shichi-gatsu (July) now".