How to find the sum of array elements in JavaScript?

Hello everyone! I just started learning JavaScript and ran into a problem. I have an array of numbers, for example: ```javascript let numbers = [10, 20, 30, 40, 50]; ``` I need to get the sum of all elements of this array, that is, the result: 150. I tried to do it manually using a loop, but my code doesn't work: ```javascript let sum = 0; for (let i = 0; i <= numbers.length; i++) { sum += numbers[i]; } console.log(sum); // Outputs NaN ``` I understand that something is wrong with the loop condition, but I can't figure it out. I also heard that JavaScript has some built-in methods for working with arrays, for example, `reduce()`. But I don't know how to use them correctly. Please tell me how to correctly find the sum of array elements? Preferably with examples and explanations for beginners.