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# what is 400 cm converted to mm?

### 8 Answers

- DrewLv 51 decade agoFavorite Answer
Remember these steps:

- - - - - - - - - - - - - - - - - - - - - - - - - ____

- - - - - - -- - - - - - - - - - - - - ______| kilo

- - - - - - - - - - - - - - ______| hecto

- - - - - - - - - - -____| deka

- - - - - - - ____| 1

- - - -____| deci

____| centi

milli

These are the prefixes that go in front of "meter" or "liter" or whatever. If you have a number and you want to convert it from one unit to another, you either go up the steps or down the steps. It takes more of the "little pieces" on lower steps to equal a "bigger piece" on the upper steps. For example, if you have 1 kilometer, and you want to know how many centimeters that is, remember that it takes more "little centimeters" to make a big kilometer. So when you go down the steps, you multiply by 10 for each step. If you go up the steps, you divide by 10 for each step. The trick is to memorize the steps.

Your problem says to convert 400 cm to mm. Remember that a cm is bigger than a mm, so it takes more mm to equal the same number of cm. So you have to multiply by 10 for each step. mm is one step down from cm, so you would multiply by 10. 400 cm = 400 x 10 mm = 4000 mm.

Another approach is to use the steps to remember how many of one unit equals one of another unit. Since you are moving from cm to mm, you want to get rid of cm and end up with mm. So multiply your original number by a factor that will get rid of cm and leave you with mm, like this:

10 mm = 1 cm

400 cm x (10 mm / 1 cm) = 4000 mm

Note that cm divides out and leaves you with mm, and then you do the numbers.

Source below is a good explanation.

Hope this helps!

Source(s): http://www.lessontutor.com/lw_decimals2.html - sp33dstixLv 41 decade ago
Google says:

"400 cm = ? mm"

400 centimeters = 4000 millimeters

Source(s): www.goooooogle.com - NumbatLv 61 decade ago
Well, it is obviously 4000 mm (a cm is 10mm). However, it is also 4 metres and it is conventional to use the common base unit if possible.

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