Ordered list is created using <ol> </ol> Tag. The attribute type may be ‘a’, ‘A’, 1,1, ‘i’, etc. On the face of it, ordered lists look a lot like unordered lists, and a lot of the same rules apply to both constructs. The only difference in HTML is that instead of using <UL> and </UL>, an ordered list is contained within the tags <OL> and </OL>. Ordered lists are based on list items, just as unordered lists are.
However, when an ordered list is displayed in a Web browser, it uses an automatically generated sequence of item markers. In other words, the items are numbered. 

The markup for a simple ordered list, based on the first example in this chapter :

<OL>
<LI>Monday
<LI>Tuesday
<LI> Wednesday
<LI>Thursday
<LI>Friday
</OL>

The above markup will look similar to the previously discussed simple unordered list, with the important difference that each day of the week is numbered instead of preceded by a “bullet.” 

In other words, it looks like this :

Monday
Tuesday
Wednesday
Thursday
Friday

Ordered lists are as nestable as unordered lists, and you can nest unordered lists in ordered lists, as well as the other way.