round a number to the nearest ten thousandth in ruby

To round a number to the nearest ten thousandth in Ruby, we can use the round method from the Math module. Here's an example:

main.rb
num = 1234.56789
rounded_num = (num * 10000).round / 10000.0
puts rounded_num # Output: 1234.5679
98 chars
4 lines

In the example above, we first multiply the number by 10000 to move the decimal point four places to the right. Then we use the round method to round the number to the nearest integer. Finally, we divide the rounded number by 10000.0 to move the decimal point back to its original position.

Note that we're using the .0 at the end of 10000 to ensure that the division is being performed with floating point arithmetic.