I need to download numbers for my MacBook Air 2017

The current Numbers app requires macOS 14 Sonoma or later. If your Mac is not capable running macOS Sonoma then you can't directly get the numbers app.

If you had downloaded before with the Apple ID being used on the Mac, you may be able to download a compatible version from your purchase history.

click here ➜ Redownload apps and games from Apple - Apple Support

If not, then your only options is to use a 3rd party app such as LibreOffice instead.

If you never installed Apple's Numbers application since Oct 2013, or it came pre-installed, then you can not install the last compatible version (13.1) for Monterey by any means as Apple provides no separate download access for the application installer. You would need to use Numbers for iCloud instead.

If you installed Numbers for macOS since the above date, then you may be able to get Numbers for Monterey in the following manner:

• Launch the Mac App Store and sign in with the same Apple ID as you used previously to install Numbers
• Press cmd+0 (zero) to open the Purchased panel.
  • If Numbers is there, it should have some symbology offering a download. Click that and do not click Cancel on any subsequent dialogs. It should offer to install the last compatible version of Numbers for Monterey.
  • If Numbers is not present on the Purchased panel, then you are done.