How to hide/show component using ngif based on boolean from separate component

Question

I'm trying to show/hide an element in a parent component when the user clicks on a button from the child component. I'm not sure if I'm doing something wrong or maybe I have the complete wrong approach

Parent Component

<div *ngIf="show">Hello World</div>
<div *ngIf="!show">Goodbye World</div>

Child Component

<button (click)="showHello()">
 <i class="fas fa-plus"></i>
</button>

Child Component .ts file

show: boolean = false;

showHello() {
    this.show = !this.show;
    console.log('show', this.show);
 }

Answer 1

parent:

<hello #hello></hello>
<p>
  {{hello.show}}
</p>

child:

import { Component, Input } from '@angular/core';

@Component({
  selector: 'hello',
  template: `<button (click)="showHello()">
              Show
              </button>`,
  styles: [`h1 { font-family: Lato; }`]
})
export class HelloComponent  {
  show: boolean = false;

  showHello() {
      this.show = !this.show;
      console.log('show', this.show);
  }
}

Live demo