The **`round()` function** rounds off a number to a specified number of decimal places. 

Figure 1 shows a visual representation of the `round()` function.

# Syntax
```ruby
num.round(ndigits)
#where num is the number which is to be rounded off
#where ndigits is the number of decimal places
```
# Parameter
The parameter **`ndigits`** is the number of decimal places to which the above number needs to be rounded off. 
>This is an optional parameter. Its default value is 0. If  `ndigits` is omitted, then `round()` returns the nearest integer value of a number.    

# Return value
The **`round()`** function returns the number rounded off to the specified number of decimal places. 


> If you input a negative value (`-n`) in the `ndigits`, then `n` digits to the left of the decimal point of the number will be rounded off.

# Example

#number: postive ndigits: positive
print "(9.8923).round(2):", (9.8923).round(2), "\n"

#number: negative ndigits: positive
print "(-9.8923).round(2): ", (-9.8923).round(2), "\n"

#number: positive ndigits: negative
print "(923.8923).round(-2): ", (923.8923).round(-2), "\n"
print "(989.8923).round(-2): ", (989.8923).round(-2), "\n"

#number: negative ndigits: negative
print "(-923.8923).round(-2): ", (-923.8923).round(-2), "\n"
print "(-989.8923).round(-2): ", (-989.8923).round(-2), "\n"

# no ndigits
print "(9.8923).round():", (9.8923).round(), "\n"
print "(-9.8923).round(): ", (-9.8923).round(), "\n"

What is round() in Ruby?

The round() function in Ruby rounds a number to a specified number of decimal places, defaulting to 0 if omitted.