## Explanation

In this example, the goal is to answer the question "What percentage of students were absent from each class". In other words, given a class with 30 students total, 27 of which were present, we want to return 10% absent. The general formula for this calculation, where "x" is the percent absent is:

```
x=absent/total
```

However, since we don't have a column for the number of students absent in the table, we need to calculate this number as part of the formula:

```
x=(total-attended)/total
x=(30-27)/30
x=3/30
x=0.10
```

After we convert this to an Excel formula with cell references, the formula in E5 becomes:

```
=(C5-D5)/C5
=(30-27)/30
=3/30
=0.10
```

As the formula is copied down, the formula returns calculated "percent absent" for each class listed in the table. These results are decimal numbers formatted with the Percentage number format.

### Formatting percentages in Excel

In mathematics, a percentage is a number expressed as a fraction of 100. For example, 55% is read as "Fifty-five percent" and is equivalent to 55/100 or 0.55. To display values like this with with a percent sign (%), apply Percentage number format.