What is the correct expression of 10/20, 20/30, 30/40 etc?


On a news report, I heard the phrase 四五{しご}十{じゅう}メートル and it got me thinking
about how to express other number approximations. Are the following correct?

  * 10 or 20 meters じゅうにじゅうメートル 
  * 20 or 30 meters にさんじゅうメートル
  * 30 or 40 meters さんよんじゅうメートル
  * 40 or 50 meters しごじゅうメートル
  * 50 or 60 meters ごろくじゅうメートル
  * 60 or 70 meters ろくななじゅうメートル
  * 70 or 80 meters ななはちじゅうメートル
  * 80 or 90 meters はちきゅうじゅうメートル
  * 90 or 100 meters きゅうじゅうひゃくメートル




いちに, にさん, さんよん (or さんし), しご, ごろく, ろくしち (or ろくなな) and しちはち (or ななはち) are very
common and handy expressions. はちきゅう is understood, but is relatively less
common. We don't use よんご for some reason. They are used like this:

  * いちにかい: once or twice
  * にさんにち: 2 or 3 days
  * さんよんまんえん: 30000-40000 yen
  * ごろっぴゃくねん: 500-600 years
  * しちはっぽん: 7 or 8 (e.g. pencils)

It's even possible to say:

  * よんじゅうごろっキロ: 45-46 kg/km
  * せんろくななひゃっかい: 1600-1700 times

But じゅうにじゅうメートル and きゅうじゅうひゃくメートル are wrong. In these cases, you have to use
から (or [ないし](https://japanese.stackexchange.com/q/46524/5010)) explicitly and
say:

  * じゅう から にじゅうメートル: 10-20 meters
  * きゅうじゅう から ひゃくメートル: 90-100 meters

You also have to use から explicitly when you want to say 50-70, for example.

  * ごじゅう から ななじゅうえん: 50 to 70 yen  
(ご から ななじゅうえん is also acceptable when there is no chance for misunderstanding)

Related: [How to read: the "~" (tilde) in "3~4
行"](https://japanese.stackexchange.com/q/21679/5010)




いちに, にさん, さんよん (or さんし), しご, ごろく, ろくしち (or ろくなな) and しちはち (or ななはち) are very
common and handy expressions. はちきゅう is understood, but is relatively less
common. We don't use よんご for some reason. They are used like this:

  * いちにかい: once or twice
  * にさんにち: 2 or 3 days
  * さんよんまんえん: 30000-40000 yen
  * ごろっぴゃくねん: 500-600 years
  * しちはっぽん: 7 or 8 (e.g. pencils)

It's even possible to say:

  * よんじゅうごろっキロ: 45-46 kg/km
  * せんろくななひゃっかい: 1600-1700 times

But じゅうにじゅうメートル and きゅうじゅうひゃくメートル are wrong. In these cases, you have to use
から (or [ないし](https://japanese.stackexchange.com/q/46524/5010)) explicitly and
say:

  * じゅう から にじゅうメートル: 10-20 meters
  * きゅうじゅう から ひゃくメートル: 90-100 meters

You also have to use から explicitly when you want to say 50-70, for example.

  * ごじゅう から ななじゅうえん: 50 to 70 yen  
(ご から ななじゅうえん is also acceptable when there is no chance for misunderstanding)

Related: [How to read: the "~" (tilde) in "3~4
行"](https://japanese.stackexchange.com/q/21679/5010)

