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{{lua|Module:Math}}

==Usage==
This template rounds parameter 1 by parameter 2 decimal places (goes the other way for negative rounding) and includes trailing zeros.
::: {{tlx|rnd|54.376|2}} &nbsp; &nbsp; gives {{rnd|54.376|2}}
::: {{tlx|rnd|54.376|-1}} &nbsp; gives {{rnd|54.376|-1}}
::: {{tlx|rnd|68.4273E12|-10}} gives {{rnd|68.4273E12|-10}}
For example, rounding by 1 gives 1 decimal digit, rounding by&nbsp;0 gives integers, or rounding by&nbsp;-2 gives the amount in hundreds. [[Scientific notation]] is displayed for numbers greater than or equal to 1{{e|9}}, or less than 1{{e|−4}}.

'''Examples:'''
*{{tlx|rnd|2.0004|3}} gives {{rnd|2.0004|3}}
**whereas {{tlx|#expr:2.0004 round 3}} gives {{#expr:2.0004 round 3}}
*{{tlx|rnd|0.000020004|7}} gives {{rnd|0.000020004|7}}
*{{tlx|rnd|0|8}} gives {{rnd|0|8}}
*{{tlx|rnd|154268|-3}} gives {{rnd|154268|-3}}
*{{tlx|rnd|154568|-3}} gives {{rnd|154568|-3}}
*{{xpsoc|rnd|1200004|-1}}
**whereas {{xpsoc|#expr:1200004round-1}}, even though  {{xpsoc|#expr:1300004round-1}} (see [[m:Help:Format produced by expr]]) 
*{{xpsoc|rnd|1300004|-1}}
*{{xpsoc|rnd|4.1e6|9}}
*{{xpsoc|rnd|4.1e6|10}}
*{{xpsoc|rnd|1542689271|-7}}
*{{xpsoc|rnd|1542689271|2}}
*{{xpsoc|rnd|7e9|-9}}
*{{xpsoc|rnd|-123|1}}
*{{xpsoc|rnd|-1200007|-2}}
*{{xpsoc|rnd|-1234567899|-7}}
As with #expr, the total number of significant digits is not more than 14:
*{{xpsoc|rnd|1234567890.123456789|10}}
*{{xpsoc|rnd|123456789.0123456789|10}}
*{{xpsoc|rnd|.0001234567890123456789|20}}

==Internal details==
The markup-based version of Template:rnd uses three subtemplates:
*{{tl|rnd/-}} — for trailing zeros
*{{tl|rnd/e+}} — for scientific notation for numbers greater than or equal to 10<sup>9</sup> or less than or equal to −10<sup>9</sup>
*{{tl|rnd/e−}} — for scientific notation for numbers greater than −10<sup>−4</sup> and less than 10<sup>−4</sup> but not equal to zero

The [[Lua script|Lua]]-based version of {{tlx|rnd}} uses [[Module:Math]] and always has an expansion depth of 3. However, the markup-based version has an expansion depth of 9–15, which depends on the size of the numbers (integer results use depth 9, decimals use depth 12), where astronomical numbers can hit expansion depth of 15 levels, for {{tlx|rnd|56.44e33|-32}}&nbsp;&rarr; 5.64&nbsp;× 10<sup>34</sup>.

===TemplateData===
{{TemplateDataHeader}}
<templatedata>{
"description": "Rounds (parameter 1) by (parameter 2) decimal places, and formats. Scientific notation is used for numbers greater than 1×10^9, or less than 1×10^−4.",
"params": {
  "1": {
    "label": "number",
    "description": "The number to be rounded",
    "type": "number",
    "required": true
  },
  "2": {
    "label": "decimal places",
    "description": "The number of decimal places, if negative the number is rounded so the last (parameter 2) digits are zero",
    "type": "number",
    "required": true
  }
}}</templatedata>


==See also==
*{{tl|rndfrac}}
*{{tl|rndnear}}
*{{tl|rndgaps}}
*{{tl|decimals}}

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[[Category:Mathematical function templates]]
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