Numbers on High Sierra 10.13.6

If you have not installed Numbers or Pages since October 2013 from the Mac App Store, you cannot get the last compatible version for any macOS version older than Monterey.

If you have purchased Numbers or Pages at any time since October 2013, open the Mac App Store & hold down the option key while clicking the Purchases tab on your High Sierra Mac. If you see Pages, Numbers, and Keynote with Update/Install buttons, it may offer to download a previous version of these applications compatible with High Sierra.

In Mojave and later releases of macOS, one must enter ⌘+0 (zero) to get to the previous purchases panel in the Mac App Store. This changed from the option+Purchases tab in High Sierra and earlier.

See VikingOSX’s reply in this discussion in the Pages for Mac forum.

In the App Store.

https://apps.apple.com/us/app/numbers/id409203825?mt=12