While not suggesting that you don't have an unexpected problem with your own iPad, I am unable to replicate the problem that you describe with Spotlight.
Using your own example - with an iPad Pro running iPadOS 26.4.1 - using Spotlight to perform the simple "2+2" calculation...
Spotlight is obviously a convenient method of performing a calculation quickly, however, there are multiple free calculator Apps (including the Apple's own Calculator App) that can be used to perform both simple or more complex calculations and conversions with relative ease. For information, if the native Appls Calculator App for iPad is not already installed on your iPad, it can be downloaded from the Apple App Store:
https://apps.apple.com/app/calculator/id1069511488
NB: If installing Apple's own Calculator App from the App Store, be aware that there are other Calculator Apps within the App Store that are visually very similar to the "official" Apple Calculator App. Using the link I have provided will find the "real" App from Apple that costs nothing at all, without risk of installing a similar App that may hide an unexpected cost or subscription.
Returning to your problem with Spotlight, if your iPad is not operating as expected, here are some troubleshooting steps that you might constructively try...
Begin with a forced-restart - as this will often clear an isolated software issue:
Force restart iPad (models with Face ID or with Touch ID in the top button)
If your iPad doesn’t have the Home button, do the following:
- Press and quickly release the volume button nearest to the top button.
- Press and quickly release the volume button farthest from the top button.
- Press and hold the top button.
- When the Apple logo appears, release the top button.
If the problem persists after performing the restart, it may be necessary to reset your iPad settings. While this reset will not cause any loss of data, as a precaution, it is always wise to ensure that you have a current iCloud or iTunes backup before performing the reset:
How to back up your iPhone, iPad, and iPod touch - Apple Support
When you are happy to proceed, you can perform the reset from iPad settings:
Settings > General > Transfer or Reset iPad > Reset > Reset All Settings
If the problem still doesn’t clear, the next step is to reset the iPad to factory settings:
Restore your iPhone, iPad, or iPod to factory settings - Apple Support
Otherwise, you would be well advised to seek assistance directly from Apple Support. You can contact the Support Team using the Support link at top-right or bottom-left of this page. Alternatively and perhaps easier, you can initiate and manage your support cases using the excellent Apple Support App. If not already installed on your iPad, the App can be downloaded from the App Store:
https://apps.apple.com/app/apple-support/id1130498044
You might also visit the Genius Bar at your local Apple Store or Apple Authorised Service Provider (AASP) - where the technicians will be able to test and assess your iPad - and you can explore your available options:
Genius Bar Reservation and Apple Support Options - Apple
