Big Numbers Logic

A correspondance between Japanese and English for big numbers: 10K up to a U.S trillion.

Base units formulas:
Man (万) : 10,000 (10K)
Oku (億) : 100,000,000 (100M)
Choo (兆) : 1,000,000,000,000 (1T)

Gotta simply multiply the base unit by the appended number: Juu (十) : 10, Hyaku (百) : 100 or Sen (千) : 1,000.

It's easier to do the math when multiplying by 10 step by step.
Examples
千万 (Ten million) would be
Man is 10K, x10 = 100K, x10 = 1M, x10 = 10M
十億 (A billion) would be
Oku is 100M, x10 = 1B

When translating big numbers (over 1K) from Jap to Eng or vice versa goes like this
1 - Identify where we are in terms of Man, Oku or Choo units. （...）
2 - Regroup the number into groups of 4 digits instead of 3, or alternatively (...)
Also make sure to say the leading number integrally before appending Man, Oku or Choo.
Examples (...)
3 - Make sure to read the subsequent portions accordingly. For example, Sen comes after Man, Man after Oku, Oku after Choo, etc. (...) Examples (...)

Examples (Eng to Jap)
17,845 regroups in 4 digits as 1,7845, or since we know it's Man, we'll take the first digit as the Man unit (since the multiplier here is 1 and there's only digit), so 一万七千八百四十五 (Ichi-man, nana sen, happyaku, yon-juu, go) - A common mistake here would've been to skip the unit regrouping part and start by translating 17 (じゅうなな / Juu-nana)