Sass/Scss - Rounding down with decimal places - responsive-design

Question

I have the following Sass rule:
$multiplier: 1/3*100;
.ratio_1x0-5{
padding-bottom: 0.5%*$multiplier;
}
Which outputs the following css:
.ratio_1x0-5{
padding-bottom: 16.6666666667%
}
Instead - I need this rule to be the following (the decimal precision isn't important - only that the last value is a 6 - not a 7), this is to resolve a subpixel rendering issue.
.ratio_1x0-5{
padding-bottom: 16.6666%
}
If I use the sass 'floor' function - it rounds down the whole thing to '16%'. Is there any way to round down to x number of decimal places in Sass? How about using a mixin to do this? I'm using libsass (sass 3.2).
Adjusting the 'precision' doesn't work - the last value is still '7'. Changing precision alone only truncates the number of decimal places - it doesn't round the last decimal place down like I need it to.
Codepen: http://codepen.io/calumbrodie/pen/aOzVga
Edit: Whoever marked this as a duplicate - this is a different question, the other question is about 'precision', while I explicitly explain why this isn't about 'precision'. I can't really make it any clearer.

Answer 1

Found the answer just after posting thanks to the following Gist:
https://gist.github.com/terkel/4373420
#function decimal-round ($number, $digits: 0, $mode: round) {
$n: 1;
// $number must be a number
#if type-of($number) != number {
#warn '#{ $number } is not a number.';
#return $number;
}
// $digits must be a unitless number
#if type-of($digits) != number {
#warn '#{ $digits } is not a number.';
#return $number;
} #else if not unitless($digits) {
#warn '#{ $digits } has a unit.';
#return $number;
}
#for $i from 1 through $digits {
$n: $n * 10;
}
#if $mode == round {
#return round($number * $n) / $n;
} #else if $mode == ceil {
#return ceil($number * $n) / $n;
} #else if $mode == floor {
#return floor($number * $n) / $n;
} #else {
#warn '#{ $mode } is undefined keyword.';
#return $number;
}
}
Then use it as follows:
.ratio_1x0-5{
padding-bottom: decimal-round(0.5%*$multiplier, 5, floor);
}

Answer 2

use $sass-precision: x;
it would tell sass explicitly what to round to in terms of decimal places.