computed:{
    sum(){
        return parseFloat(this.form.add1) + parseFloat(this.form.add2) 
    }
}
v-model = 'sum'

發(fā)送數(shù)據(jù)的時(shí)候把sum加上去

r1

           <el-form-item label="實(shí)收總金額">
             <el-input placeholder="實(shí)收總金額"  v-model="form.sum"></el-input>
           </el-form-item>
    <el-form-item label="活動(dòng)性質(zhì)">
      <el-checkbox-group v-model="form.type"
                         :max="5">
        <el-checkbox v-for="(item,index) in arr"
                     :label="item.name"
                     :key="item.id"
                     name="type"
                     @change="fun(index)">
          <div class="displayInput"
               v-if="item.change">{{item.name}}
            <span class="wrap">
              <el-input placeholder="應(yīng)收金額" v-model="form.add1"></el-input>
              <el-input placeholder="實(shí)收金額" v-model="form.add2"></el-input>
            </span>
          </div>
        </el-checkbox>
      </el-checkbox-group>
      // js data里 把form放到arr里面 
      arr：[{name:'s',form:{add1:null,add2:null}}]
      computed:{
        sum(){
            return this.arr..map(v => parseFloat(v.form.add1) + parseFloat(v.form.add2)).reduce((a, b) => a + b)
        }
    }
    // 發(fā)送數(shù)據(jù)就要你自己組織了