using @output with EventEmitter in angular

child.component.ts

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

//define the event emitter
 @Output()
 change: EventEmitter<number> = new EventEmitter<number>();
 
 //emit the event with the above change event
 this.change.emit(11); //11 will be emitted to the parent

@output()
change: EventEmitter = new EventEmitter();