Vue.js/Nuxt.js - How to pass props to slots?

So i have one grandparent component which has this code:

<template>
  <div>
      <Question qtype="single" qroot="1">
        <Answer qpoints="5" aid="1" qcorrect>Option 1</Answer>
        <Answer qpoints="0" aid="2">Option 2</Answer>
      </Question>
  </div>
</template>
<style>
</style>
<script>
import Question from "~/components/render/Question";
import Answer from "~/components/render/Answer";
export default {
  components: {
    Question,
    Answer
  }
};
</script>

Parent component:

<template>
  <div>
        <slot v-bind="$props"></slot>
  </div>
</template>
<style>
</style>
<script>
export default {
  props: ['qtype','qroot']
};
</script>

Child:

<template>
  <div>
    {{$props}}
    <li style="clear: left;">
      <input v-if="qtype == 'single'" :id="'qid-'+qid" type="radio" :name="qroot" :value="qid" style="float:left" />
      <input v-if="qtype == 'multiple'" :id="'qid-'+qid" type="checkbox" :name="qroot" :value="qid" style="float:left" />
      <label style="float:left;margin-left:5px" :for="'qid-'+qid">
        <slot></slot>
      </label>
    </li>
  </div>
</template>
<style>
</style>
<script>
export default {
   props: ["qtype", "qpoints", "qcorrect", "qroot", "aid"]
};
</script>

I tried to use v-bind, regular prop passing like this ':qtype="qtype"' but it doesn't seem to work. How can i pass "qtype" and "qroot" props to the grandchild component?