Question: By default, ordered list use _____ sequence of numbers

Answer:

The default numbering style for ordered lists in HTML is decimal. It uses sequential numbers starting from 1 and increments by one for each subsequent item. The numbers are represented using Arabic numerals (0-9). Here's an example:

```html
<ol>
<li>First item</li>
<li>Second item</li>
<li>Third item</li>
</ol>
```

In this example, the ordered list will be displayed as:

1. First item
2. Second item
3. Third item

The default numbering style can be overridden or customized using CSS by applying different properties and values to the ordered list.

```html
<ol>
<li>First item</li>
<li>Second item</li>
<li>Third item</li>
</ol>
```