我這邊的v-model，怎么是 [object HTMLInputElement] ？Vue版本3.0.0-beta.1

<template>
????<div?class="hello">
????????<input
????????????type="text"
????????????ref="num1"
????????????v-model="num1"
????????????@keyup="add()"
????????/>
????????<span>+</span>
????????<input
????????????type="text"
????????????ref="num2"
????????????v-model="num2"
????????????@keyup="add()"
????????/>
????????<span>=</span>
????????<span>{{result}}</span>
????</div>
</template>
<script>
import?{?ref?}?from?'vue'

export?default?{
????name:?'HelloWorld',
????setup?()?{
????????let?num1?=?ref(0)
????????let?num2?=?ref(0)
????????let?result?=?ref(0)

????????function?add?()?{
????????????return?result?=?(+num1)?+?(+num2)
????????}

????????return?{
????????????num1,
????????????num2,
????????????result,
????????????add,
????????}
????},
}
</script>
<style?scoped?lang="scss">
</style>

{
??"name":?"vue3-demo",
??"version":?"0.1.0",
??"private":?true,
??"scripts":?{
????"dev":?"npm?run?serve",
????"serve":?"vue-cli-service?serve",
????"build":?"vue-cli-service?build"
??},
??"dependencies":?{
????"core-js":?"^3.6.5",
????"vue":?"^3.0.0-beta.1",
????"vue-router":?"^4.0.0-alpha.6",
????"vuex":?"^4.0.0-alpha.1"
??},
??"devDependencies":?{
????"@vue/cli-plugin-babel":?"~4.5.0",
????"@vue/cli-plugin-router":?"~4.5.0",
????"@vue/cli-plugin-vuex":?"~4.5.0",
????"@vue/cli-service":?"~4.5.0",
????"@vue/compiler-sfc":?"^3.0.0-beta.1",
????"sass":?"^1.26.5",
????"sass-loader":?"^8.0.2",
????"vue-cli-plugin-vue-next":?"~0.1.4"
??}
}