XML - Quoting Numerical Attributes

Question

Should numerical attributes in XML be quoted?

<root>
  <node size=45 />
  <foo bar=1.2>
    <baz foo=20>
  </foo>
</root>

vs.

<root>
  <node size="45" />
  <foo bar="1.2">
    <baz foo="20">
  </foo>
</root>

---

My code editor/browser seems fine without quotes, but most online resources seem to say they're required.

Answer 1

http://www.w3schools.com/xml/xml_attributes.asp

XML Attributes Must be Quoted

Attribute values must always be quoted. Either single or double quotes can be used. For a person's sex, the person element can be written like this:

<person sex="female">

or like this:

<person sex='female'>

If the attribute value itself contains double quotes you can use single quotes, like in this example:

<gangster name='George "Shotgun" Ziegler'>

or you can use character entities:

<gangster name="George &quot;Shotgun&quot; Ziegler">

Updated to expand based on the newest comment, according the Microsoft universe at least.

XElement.Value Property

public string Value { get; set; }

You can also see refer to this question as well