why does the 1099 DIV line display one number and when I click on that number a smaller number is displayed in the pop up window?

Yes, you are correct, your exempt interest dividends will cause your dividend amount to appear to be smaller than what you reported.

You should report your exempt dividends on your tax return because dividends exempt from interest might be subject to the Alternative Minimum Tax (AMT).

Your taxable dividends will be shown on line 3b of your tax return.

An exempt-interest dividend is a distribution from a mutual fund, most often from a mutual fund that invests in municipal bonds, that is not subject to federal income tax. 

Exempt interest dividends are reported to a taxpayer on Form 1099-DIV in Box 12. Your Form 1099-DIV should be entered as it is shown on your form.

You can enter your Form 1099-DIV into TurboTax as follows:

1. Click on "Search" at the upper right of your screen.
2. Enter "1099-DIV"
3. Select "Jump to 1099-div"
4. Answer "Yes" to "Did you have investment income in 2024?"
5. Select "Skip Import" on the screen that asks "Let Us Enter Your Bank and Brokerage Tax Documents"
6. Select the box that says "Dividends 1099-Div" (the box will turn green with a checkmark on it)
7. And "Continue"
8. Enter your 1099-DIV information and select "Continue"
9. Answer the follow-up screens about your dividend interest
    

Click here for "Where Do I Enter Form 1099-DIV in TurboTax Online?"

Click here for "What is IRS Form 1099-DIV"