You can wrap that in an array formula like so:

```
=SUM(IF(G2:Z2 - G1:Z1 > 0, G2:Z2 - G1:Z1, 0))
```

Then to enter it as an array formula, hold `SHIFT`

and `CTRL`

while pressing `ENTER`

.

If you did it right, it will be surrounded with curly brackets when you select the cell:

```
{=SUM(IF(G2:Z2 - G1:Z1 > 0, G2:Z2 - G1:Z1, 0))}
```

Note that you should not type the curly brackets.

As a side note, I would normally recommend using the `MAX`

function to test for 0 in cases like this. It simplifies the formula from this:

```
=IF(G2:Z2 - G1:Z1 > 0, G2:Z2 - G1:Z1, 0)
```

To this:

```
=MAX(G2:Z2 - G1:Z1, 0)
```

However, this simply will not work in an array formula because the `MAX`

function aggregates the array similar to `SUM`

, meaning that in this case, it first finds the max of `G2:Z2 - G1:Z1`

and then finds the max between that max and zero, which is definitely not what we were attempting to do.