# How many millimeters are in 3 km?

Sep 9, 2016

$3 K m = 3 , 000 , 000 m m$

#### Explanation:

The units from Biggest on the left to smallest on the right are:

$\textcolor{red}{K m} \textcolor{w h i t e}{\times x} H m \textcolor{w h i t e}{\times x} D m \textcolor{w h i t e}{\times x} \textcolor{red}{m} \textcolor{w h i t e}{\times x} \mathrm{dm} \textcolor{w h i t e}{\times x} c m \textcolor{w h i t e}{\times x} \textcolor{red}{m m}$

The conversion factor between any of the adjacent units is 10.

$\leftarrow \times 10 \mathmr{and} \rightarrow \div 10$

$K m \times 1000 \rightarrow m \times 1000 \rightarrow m m$ To convert big to small.

$K m \leftarrow 1000 \div m \leftarrow 1000 \div m m$To convert small to big.

When you convert a value to a bigger unit, the number gets smaller. (There are fewer of them.) This is done by dividing

When you convert a value to a smaller unit, the number gets bigger.(There are more of them.) This is done by multiplying.

Km is the biggest distance of the metric system. (Just more than half a mile.)

mm the smallest of the usual lengths in the metric system.
(About 25 mm makes 1 inch)

To convert 3 Km to mm, write 3 under Km and fill in a 0 under each of the other units

$\textcolor{red}{K m} \textcolor{w h i t e}{\times x} H m \textcolor{w h i t e}{\times x} D m \textcolor{w h i t e}{\times x} \textcolor{red}{m} \textcolor{w h i t e}{\times x} \mathrm{dm} \textcolor{w h i t e}{\times x} c m \textcolor{w h i t e}{\times x} \textcolor{red}{m m}$

$\textcolor{red}{3} \textcolor{w h i t e}{\times \times \times} 0 \textcolor{w h i t e}{\times \times x} 0 \textcolor{w h i t e}{\times \times} \textcolor{red}{0} \textcolor{w h i t e}{\times \times} 0 \textcolor{w h i t e}{\times \times} 0 \textcolor{w h i t e}{\times \times} \textcolor{red}{0.}$

The decimal point shows what the unit is.

$3 K m = 3 , 000 , 000 m m$

$3 K m \times 1000 \rightarrow 3000 m \text{ then } \times 1000 \rightarrow 3 , 000 , 000 m m$