Vue computes attribute computed that no direct arguments can be passed
You can use closure functions to implement the need to pass parameters

<template>
  <span>{{fmtWeight(1)}}</span>
</template>

<script>
export default {
  data() {
    return {
      weight: 100
    };
  },
  computed: {
    fmtWeight() {
      return num => {
        return this.weight.toFixed(num)
      }
    }
  }
};
</script>