Exponential Notation 

Exponential notation lets you move the decimal point in a number.
It simplifies numbers by getting rid of zeros, and making math easier.
1,000,000. can be rewritten as
1. × 10^{6} with the ^{6} saying the decimal has moved
6 steps left.
0.001 can be rewritten as
1. × 10^{3} with the ^{3} saying the decimal has
moved 3 steps right.
1. × 10^{0} is just 1., since ^{0} means the decimal
hasn't been moved.
Three billion, 3,000,000,000. is just 3. × 10^{9}. (You can count the steps yourself!.)
You see...  10^{a} × 10^{b} = 10^{ a + b } 10^{a} / 10^{b} = 10^{ a  b } 
10^{a} × 10^{b} = 10^{ a + b } 10^{a} / 10^{b} = 10^{ a  b } (10^{a})^{+p} = 10^{ a × p } (10^{a})^{r} = 10^{ a / r } (A × 10^{a}) × (B × 10^{b}) = (A × B) × 10^{ a + b } (A × 10^{a}) / (B × 10^{b}) = (A / B) × 10^{ a  b } (A × 10^{a})^{+p} = A^{+p} × 10^{ a × p } (A × 10^{a})^{r} = A^{r} × 10^{ a / r } (A × 10^{same}) + (B × 10^{same}) = (A + B) × 10^{same} (A × 10^{same})  (B × 10^{same}) = (A  B) × 10^{same} (B × 10^{bigger}) + (S × 10^{smaller}) = B × 10^{bigger} (B × 10^{bigger})  (S × 10^{smaller}) = B × 10^{bigger} (S × 10^{smaller}) + (B × 10^{bigger}) = B × 10^{bigger} (S × 10^{smaller})  (B × 10^{bigger}) = B × 10^{bigger} And if doing "order of magnitude calculation":
10^{same} + 10^{same} ~= 10^{same} 10^{same}  10^{same} ~= don't do it 10^{bigger} + 10^{smaller} ~= 10^{bigger} 10^{bigger}  10^{smaller} ~= 10^{bigger}
Comments encouraged.  Mitchell N Charity <mcharity@lcs.mit.edu >) 
Doables: This could use an overhaul. And page of `how to' and examples. Perhaps absorb sci note's links aswell. History: 2002.Mar.05 Changed × (×) x symbols to × (×), and upgraded HTML, to work around a reported Mac Netscape problem. Fixed ChemTeam link. 1998.Sep.22 Added link to `how to write' in Links section. Added this History section. 1997.summer Created.