Scientific notation

Scientific notation, or standard form, is a way of writing very large or very small numbers using a number between 1 and 10 multiplied by a power of ten: 

a · 10^b , where “a” is called mantissa or significand and “b” is called exponent or index.

Examples:
3.450.000.000.000 = 3.45 · 10¹²
0.0000000012 = 1.2 · 10^-9  

Exercise: Express in scientific notation:

a) 1.200.000.000.000.000

b) 0.0000000000123

c) 345.000.000.000

d) 0.000008

Solutions: a) 1.2·10¹⁵; b) 1.23·10^-11; c) 3.45·10¹¹; d) 8·10^-5