Very similar column - TEXT Filter on one sheet, NUMBER Filter on other - Why different?

I have a workbook with two sheets. On sheet one is a single column with a header and numbers below. On the second sheet is a very similar column and some other data in the sheet. My question is about Column A in both sheets. It was pointed out to me that Column A in sheet 1 is formatted differently than Column A in sheet 2.

Upon clicking Format Cells for each column, they indicate that they are "Number" and "General". However, when a filter is added to the columns, Column A on sheet 1 filters as "Numbers". Column A on sheet 2 filters as "Text". This was not done intentionally. Why would this happen?

I need to use a formula to combine and align the sheets based on information in Column A of both sheets and apparently this is messing me up. How can I make both columns to be formatted the same?

Hello AliGW.

The column in sheet 1 was made by typing the first six digit "code" number and then dragging down to the logical end amount of six digit numbers, within a structure of being restrained by the first two numbers (710000 - 719999).

The information on sheet 2 was produced (Excel report) by the program used to track this information. As you can see, the numbers in Column A in sheet 2, have breaks between the numbers. That is the difference between Column A on both sheets. That is my main purposed in this, is listing every possible number in Column A on sheet 1 and trying to bring over all the data on sheet 2, based on how they align by matching the "code" numbers on sheet 1.

For disclosure (not breaking forum rules), I already have received help on this great forum in achieving the desired end result. But, in doing so, caused me to ask the present question of the difference in filtering. I am posting the end result spreadsheet just so you can see what I am talking about. But the formula that was very generously offered to me, had a component that I did not understand (the formula negates the filtering difference).