Number 
Scientific
notation? 
124.78 

2.3
X 10^{4} 

0.3
X 10^{10} 

12.3
X 10^{14} 

1.4
X 10^{4} 

9.9
X 10^{12} 

Scientific notation 

Scientific notation is based on powers of ten. The number 2,300,000 is written
as 2.3 X 10^{6} . 

The speed of light is 300,000km/s. We can write this number as 3.0 X 10^{5}km/s The mass of a carbon atom is 0.000000000000000000000002 grams. We can write this as 2.0 X 10^{23} grams. The number of hydrogen atoms in 1 gram of hydrogen is 623,000,000,000,000,000,000,000. We can write this as 6.23 X 10^{23} . You can see why we write in scientific notation. 

To write a number in scientific notation we take two steps. Step 1 Move the decimal point to the left or right so that the coefficient is between 1 and 10. Step 2 For every decimal place the decimal point moves left or right we add or subtract 1 from the exponent. When the decimal point moves to the left we add 1 to the exponent. When the decimal point moves right we subtract 1 from the exponent. Look at the animation on the right. 

Express 0.000034 in scientific notation. Look at the animation on the right.  
Express 1,234,000 in scientific notation.  Solution  
Express 123.45 X 10^{6} in scientific notation.  Solution  
