I think rewording your conditions may help you see where you've gone wrong. Think of it this way instead:

```
If `a>0`, then `a`. Otherwise, check if `b=#N/A`.
If `b=#N/A`, then check if `c=0`. Otherwise, `b`.
If `c=0`, then `d/61`. Otherwise, `c`.
```

Note the difference between the first line and what you described. You jumped straight to "use `b`

" and then checked that `b`

met a condition after you already said to use it. This won't work in a nested conditional statement. If you conclude something, then it's done; no other conditions are checked.

To illustrate this, consider the case where `a=0`

, `b=#N/A`

, `c=0`

, and `d=61`

. You expect this to result in `1`

. Evaluating your formula would go as follows:

```
=IF(0>0,DB11,IF(ISNA(DA11),CZ11,IF(CZ11=0,BE11/61,CZ11)))
=IF(FALSE,DB11,IF(ISNA(DA11),CZ11,IF(CZ11=0,BE11/61,CZ11)))
=IF(ISNA(DA11),CZ11,IF(CZ11=0,BE11/61,CZ11))
=IF(ISNA(#N/A),CZ11,IF(CZ11=0,BE11/61,CZ11))
=IF(TRUE,CZ11,IF(CZ11=0,BE11/61,CZ11))
=CZ11
=0
```

Since the check of the condition on `b`

concludes with `c`

, the condition on `c`

is never even checked. This is the source of your error.

Here's how your formula should be constructed.

```
=IF(DB11>0,DB11,IF(ISNA(DA11),IF(CZ11=0,BE11/61,CZ11),DA11))
```

To illustrate how this works, look at the same example case as above.

```
=IF(0>0,DB11,IF(ISNA(DA11),IF(CZ11=0,BE11/61,CZ11),DA11))
=IF(FALSE,DB11,IF(ISNA(DA11),IF(CZ11=0,BE11/61,CZ11),DA11))
=IF(ISNA(DA11),IF(CZ11=0,BE11/61,CZ11),DA11)
=IF(ISNA(#N/A),IF(CZ11=0,BE11/61,CZ11),DA11)
=IF(TRUE,IF(CZ11=0,BE11/61,CZ11),DA11)
=IF(CZ11=0,BE11/61,CZ11)
=IF(0=0,BE11/61,CZ11)
=IF(TRUE,BE11/61,CZ11)
=BE11/61
=61/61
=1
```