title: Calculating numbers with vue
body: <p>I am really new to vueJS.</p>
  <p>I try to get two input value, adding them together, and show the result. I found it is really wired, because when number1 minus number3, or number1 multiplied number2, or number1 divided number2, the calculating is all working fine. However when number1 plus number2, it doesn’t working, and seems add two str together (for example: 1 + 2 = 12).</p>
  <p>What’s going on here? And how can I get result with number1 + number2</p>
  <p>Please help</p>
  <pre class="lang-html prettyprint-override"><code>    &lt;div id=&quot;app&quot;&gt;
  
              &lt;input type=&quot;number&quot; name=&quot;number1&quot; v-on:input= &quot;update_number1&quot;&gt;
              &lt;p&gt;{{ number1 }}&lt;/p&gt;
              &lt;input type=&quot;number&quot; name=&quot;number2&quot; v-on:input= &quot;update_number2&quot;&gt;
              &lt;p&gt;{{ number2 }}&lt;/p&gt;
  
              &lt;hr&gt;
              &lt;p&gt;{{ result() }}&lt;/p&gt;
  
      &lt;/div&gt;
  </code></pre>
  <pre><code>    new Vue({
        el: '#app',
        data: {
          number1: 0,
          number2: 0,
        },
        methods: {
          update_number1: function (event) {
            this.number1 = event.target.value;
          },
          update_number2: function (event) {
            this.number2 = event.target.value;
          },
          result: function () {
      
            return this.number1 + this.number2;
          },
      
        },
      });
  </code></pre>