Assuming the name you want to search for and the name as it appears in the lookup table are identical, you'll want to use a VLOOKUP formula:

```
=VLOOKUP([lookupname],[referencetable],[columnnumber],False)
```

As an example, if your name is in cell A2 and the reference table is on Sheet2 (with column A containing the name, column B containing the number, and the table spreading from row 1 to 900), your formula would look like this:

```
=VLOOKUP(A2,Sheet2!$A$1:$B$900,2,False)
```

Note the dollar signs in the formula - these "lock" references, so you can copy the formula elsewhere without the reference moving about.

The "False" tells the formula to look only for exact matches.