Hi @deokseong0499,
Welcome to the Community!
Regrettably, it's not possible. This is because your number is linked to a specific SIM card and can not be split between more.
Nonetheless, I understand Smartwatches can be paired to your mobile devices for you to enable you to access basic functions (making calls / receiving / viewing messages) by turning on the Bluetooth on your mobile device.
Regards,
