Theory:

Most common conversions used in real life:
 
1. Length:

\(1 \ km = 1000 \ m\)

\(1 \ m = 100 \ cm\)

\(1 \ m = 1000 \ mm\)
 
\(1 \ cm = 10 \ mm\)
 

2. Weight:

\(1 \ kg = 1000 \ g\)
 
\(1 \ g = 1000 \ mg\)
 

3. Volume (Capacity):

\(1 \ kl = 1000 \ l\)

\(1 \ l = 1000 \ ml\)
Example:
1. Convert \(25.38 \ km\) to \(m\).
 
\(1 \ km = 1000 \ m\)
 
To convert higher unit to lower unit, we need to multiply by power of \(10\)'s.
 
\(25.38 \times 1000 = 25380\)
 
Therefore, \(25.38 \ km = 25380 \ m\).
 
 
2. Convert \(955 \ mg\) to \(g\).
 
To convert lower unit to higher unit, we need to divide by power of \(10\)'s.
 
\(1 \ g = 1000 \ mg\)
 
11000 \(g = 1 \ mg\)
 
9551000 \(= 0.955 \)
 
Therefore, \(955 \ mg = 0.955 \ g\).
 
 
3. Express \(56 \ ml\) in \(l\).
 
To convert lower unit to higher unit, we need to divide by power of \(10\)'s.
 
\(1 \ l = 1000 \ ml\)
 
11000 \(ml = 1 \ l\)
 
561000 \(= 0.056 \)
 
Therefore, \(56 \ ml = 0.056 \ l\).