text: var app = new Vue({
      el: '#app',
      data: {
          counter: 0,
          value: 1,
          visibility: false,
          visibilityBtnText: 'Change Value'
      },
      methods: {
          add(num) {
              console.log(num);
              if(num != NaN && num != ''){
                  this.counter = this.counter + parseFloat(num);
              }
          },
          subtract(num) {
              if(num != NaN && num != ''){
                  this.counter = this.counter - parseFloat(num);
              }
          },
          reset(){
              this.counter = this.counter - this.counter;
          },
          hideOrShow(){
              this.visibility = !this.visibility;
              this.visibilityBtnText = this.visibilityBtnText == 'Change Value' ? 'Hide input' : 'Change Value';
          }
      }
  })