Hi there marimar111,
From what we can tell, the date and time cells in spreadsheets in Numbers on your iPad aren't updating as expected for the Today and Now options. We're glad you've joined us in Apple Support Communities, and we can provide some guidance.
To start, you'll want to be sure the correct function is being used for the cells you're referring to. Have a look at the links below to learn more:
Formula and Functions Help - TODAY
Formula and Functions Help - NOW
Next, make sure you're following the steps in this link to insert the function properly:
Insert formulas and functions in Numbers on iPad
Also, you may find this link helpful:
Add a date, time, or duration in Numbers on iPad
Let us know if you have any more questions.
Take care.