LWC Parent to Child Primitive Data Communication

 <template>

<c-parenttochildalertcomponent

  message = "I got the data"

  card-heading = "Parent to Child primitive data communication"

  number = 20

  is-valid >

</c-parenttochildalertcomponent>

</template>

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parenttochildalertcomponent 

<template>

<lightning-card  variant="Narrow"   icon-name="standard:account">

    <div>

        {message} 

        {cardHeading}

        {number}

        {isValid}

    </div>

</lightning-card>

</template>

import { LightningElement,api } from 'lwc';

export default class Parenttochildalertcomponent extends LightningElement {

@api message

@api cardHeading

@api number

@api isValid 

}