six significant digits

puts '%g' % 1234.567   # => '1234.57': six significant digits

1.	Display a Message
2.	Insert some output from a shell command
3.	Put two or more variables together with the + method:
4.	format a string with puts
5.	format based string interpolation
6.	Get the command line parameter
7.	Comparing Floating-Point Numbers
8.	Simple Arithmetic
9.	use parentheses
10.	Array on righthand side for multiple args
11.	%d for decimal integers
12.	hexadecimal integers
13.	uppercase hexadecimal integers
14.	octal integers string format
15.	full-length floating-point numbers
16.	force exponential notation
17.	exponential with uppercase E
18.	Use %f or %e depending on magnitude
19.	Field width
20.	Float number Precision
21.	Field and precision combined
22.	Multiple arguments to be formatted

six significant digits : puts « Language Basics « Ruby