## Explanation

In this example, the goal is to return the sum for an entire row in an Excel worksheet. One way to do this is to use a full row reference.

### Full row references

Excel supports full row references like this:

```
=SUM(1:1) // sum all of row 1
=SUM(3:3) // sum all of row 2
=SUM(4:5) // sum all of rows 4 and 5
```

You can see how this works yourself by typing 1:1 or 3:3 into the name box (left of the formula bar) and hitting return. You will see Excel select the entire row.

### Example

To solve the problem in the example worksheet, we can use a full row reference to row 5 with the SUM function like this:

```
=SUM(5:5)
```

The result is the sum of all numeric values in row 5. As the formula is copied down, we get a sum for row 6 and row 7 as well:

```
=SUM(5:5) // sum red
=SUM(6:6) // sum blue
=SUM(7:7) // sum green
```

As new entries for "Red" are added to the table in rows 5, 6, and 7, the formula will automatically include these new amounts.

### Advantages and risks

The main advantage to full row references is simplicity. Simple and very compact, a full row reference will automatically include *all data* in a row, even when data is added or removed. However, full row references come with certain risks. One risk is that you may accidentally include extra data in a calculation. For example, if you use =SUM(5:5) to sum numbers in row 5, you are targeting over 16,000 cells to the right. If row 5 includes extra dates somewhere far to the right, the numeric values of these dates will be included, and SUM will return an incorrect result.