For example,

Say the value of a cell is:

```
IF(ISNA(VLOOKUP(A3,somesheet!G:J,3,FALSE) * VLOOKUP(A3,someothersheet!A:D,4,FALSE)), 0, VLOOKUP(A3,somesheet!G:J,3,FALSE) * VLOOKUP(A3,someothersheet!A:D,4,FALSE))
```

Here, I want the product of the two VLOOKUPs. But some rows may not be there, so it could return NA. If it returns NA, just put zero in this cell, but otherwise I want the product.

It seems silly that you'd have to have that whole expression in there twice. Is there some shortcut where I can say "do this calculation, and if it returns a value, use that, but otherwise use some default value?