Функция React toDoApp, удаляющая задачу, не работает

import React from 'react';
import './App.css';

class App extends React.Component {
  constructor(){
    super();
    this.state = {
      value: '',
      tasks: []
    };

    this.handleChangeEvent = this.handleChangeEvent.bind(this)
    this.addItem = this.addItem.bind(this)
    this.removeItem = this.removeItem(this)
  }

  handleChangeEvent(event) {
      this.setState({  
        value: event.target.value
      })
  }

  addItem(){
    if (this.state.value === ''){
      alert('Enter a task!')
    } else {
      const newTask = [...this.state.tasks, this.state.value]
      this.setState({
      tasks: newTask,
      value: ''
      })
    }
    }

  removeItem(){
    this.state.tasks.pop()
    this.setState({
      tasks: this.state.tasks,
    })

  }

  render(){

    const itemList = this.state.tasks.map((num) => 
              <li>{num}</li>
            );

    return(
      <div>
              <input type = "text" value = {this.state.value} onChange = {this.handleChangeEvent}></input>
              <button onClick = {this.addItem}>+</button>
              <button onClick = {this.removeItem}>-</button>
              <ul>{itemList}</ul>  
              {this.state.tasks}


      </div>
    )
  }
}


export default App;