JSFiddle - React, Tailwind, and code Playground

HTML

<html ng-app="todoApp">  
<h2>Todo</h2>
    <div ng-controller="TodoController">
        <input type="range" min="10" max="10000" step="0.50" id="mensualite_slider" ng-model="gils" size="4" />
        <input type="text" name="mensualite" id="mensualite" ng-model="gils" size="4" /> 
        <br />
       <input type="range" min="10" max="10000" step="0.50" id="mensualite_slider_2" ng-model="gils_2" size="4" />
        <input type="text" name="mensualite_2" id="mensualite_2" ng-model="gils_2" size="4" /> 
        <br />
       <input type="range" min="10" max="10000" step="0.50" id="mensualite_slider_3" ng-model="gils_3" size="4" />
        <input type="text" name="mensualite_3" id="mensualite_3" ng-model="gils_3" size="4" /> 
        <br />
    </div>
        
 </html>

JavaScript

angular.module('todoApp', [])
  .controller('TodoController', ['$scope', function($scope) {
    $scope.gils = 1000,
    $scope.gils_2 = 500;
    $scope.gils_3 = $scope.gils + $scope.gils_2;
  }]);