Ignoring characters while formula looks for value

I have stacked formulas that look for values via vlookup and index match functions.

Sometimes the worksheet will have ( 100 ) separated into 3 columns (open parenthesis, number, closed parenthesis) and the formula will pull the first column containing the parenthesis. How can I write the formula to ignore the "(" and get to the "100"?

The formula uses ISERROR to move forward, could I incorporate ISNUMBER also or is there a better way to do this?

The workbook is set up with multiple worksheets. The first is a summary that pulls numbers from the rest of the worksheets via stacked vlookup and index/match formulas.

The remaining worksheets have data populated from converted PDFs that do not always come out evenly, in other words, a value may be in cell D100 in one sheet, but on the next worksheet the same value is in cell D101, or E100.

eg)
Worksheet 2:

| A | B | C | D | E |
1 |Dist| | ( |100| ) |
2
3

Worksheet 3:
| A | B | C | D | E |
1 |Dist| ( |100| ) | |
2
3

Worksheet 4:
| A | B | C | D | E |
1
2 | |Dist| ( |100| ) |
3

The formulas look for "Dist" and will search the range of cells in the proceeding columns for a corresponding value and if nothing is found it will move on to the next formula. Unfortunately, the formula will often return the "(". I am trying to write the formula so that it overlooks the "(" and instead returns the numerical value "100".