## Round Function Question

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Super Contributor
Posts: 339

# Round Function Question

Hi Experts,

Would like to consult regarding the round function.

Given the value 123.456 for a, how come this turns out to be the value when I use the round function.

ROUND parameter

a = 123.456

Result
b = round(a,0.01)123.46 (ok)
b = round(a,0.02)123.46 (ok)
b = round(a,0.03)123.45 (?)
b = round(a,0.04)123.44 (?)
b = round(a,0.05)123.45 (?)
b = round(a,0.06)123.48 (?)
b = round(a,0.07)123.48 (?)
b = round(a,0.08)123.44 (?)
b = round(a,0.09)123.48 (?)

Is there a bug on the round function or is there something I am not aware on how it derives into these results. Thanks!

Accepted Solutions
Solution
‎10-18-2012 05:36 AM
Super Contributor
Posts: 644

## Re: Round Function Question

The second number in the SAS round function specifies the units that should be rounded to, so for example round(123.456, .03) says round the number to the nearest multiple of .03 .  There are 4115.2 multiples of .03 in the number 123.456; rounding this to the nearest integer gives 4115 multiples.  Multiplying back correctly gives the resultant 123.45, and so for the other values of rounding unit.

 Initial value Rounding Unit Number of Multiples Multiples Rounded Multiplied back 123.456 0.01 12345.6 12346 123.46 123.456 0.02 6172.8 6173 123.46 123.456 0.03 4115.2 4115 123.45 123.456 0.04 3086.4 3086 123.44 123.456 0.05 2469.12 2469 123.45 123.456 0.06 2057.6 2058 123.48 123.456 0.07 1763.657143 1764 123.48 123.456 0.08 1543.2 1543 123.44 123.456 0.09 1371.733333 1372 123.48

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Solution
‎10-18-2012 05:36 AM
Super Contributor
Posts: 644

## Re: Round Function Question

The second number in the SAS round function specifies the units that should be rounded to, so for example round(123.456, .03) says round the number to the nearest multiple of .03 .  There are 4115.2 multiples of .03 in the number 123.456; rounding this to the nearest integer gives 4115 multiples.  Multiplying back correctly gives the resultant 123.45, and so for the other values of rounding unit.

 Initial value Rounding Unit Number of Multiples Multiples Rounded Multiplied back 123.456 0.01 12345.6 12346 123.46 123.456 0.02 6172.8 6173 123.46 123.456 0.03 4115.2 4115 123.45 123.456 0.04 3086.4 3086 123.44 123.456 0.05 2469.12 2469 123.45 123.456 0.06 2057.6 2058 123.48 123.456 0.07 1763.657143 1764 123.48 123.456 0.08 1543.2 1543 123.44 123.456 0.09 1371.733333 1372 123.48
Posts: 3,167

## Re: Round Function Question

Wow, This is awesome! I did not know that. Learn some. Thanks a lot!

Haikuo

Super Contributor
Posts: 339

## Re: Round Function Question

This is totally great explanation regarding the round function. I believe most are not also aware of this. Thank you very much! You have just expanded my knowledge!

Super Contributor
Posts: 644

## Re: Round Function Question

I can envisage there might be a situation where round(x, .02) or round(x, .05) might be required but I cannot imagine why anyone would want round(x, .03) or round(x, .07).  However, it is there if needed.  You can also round to other fractions like quarters, round(x, .25) or eighths, round(x, .125) etc.

Rounding a whole number by say .07 can yield unexpected results: round(123, .07) = 122.99 ( ! ).