Learn Recursion by Building a Decimal to Binary Converter - Step 69

Tell us what’s happening:

Describe your issue in detail here.

Your code so far

<!-- file: index.html -->
<!DOCTYPE html>
<html lang="en">
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Decimal to Binary Converter</title>
    <link rel="stylesheet" href="styles.css" />
    <h1>Decimal to Binary Converter</h1>
    <div class="input-container">
      <label for="number-input">Enter a decimal number:</label>
        name="decimal number input"
      <button class="convert-btn" id="convert-btn">Convert</button>
    <output id="result" for="number-input"></output>
    <div id="animation-container"></div>
    <script src="script.js"></script>
/* file: styles.css */
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;

:root {
  --light-grey: #f5f6f7;
  --dark-blue: #1b1b32;
  --orange: #f1be32;

body {
  background-color: var(--dark-blue);
  font-family: "Times New Roman", Times, serif;
  font-size: 18px;
  color: var(--light-grey);
  padding: 0 15px;
  display: flex;
  flex-direction: column;
  align-items: center;

h1 {
  text-align: center;
  font-size: 2.3rem;
  margin: 20px 0;

.input-container {
  margin: 10px 0;
  display: flex;
  flex-direction: column;
  gap: 10px;
  justify-content: center;
  align-items: center;

.convert-btn {
  background-color: var(--orange);
  cursor: pointer;
  border: none;
  padding: 4px;

.number-input {
  height: 25px;

#result {
  margin: 10px 0;
  min-width: 200px;
  width: fit-content;
  min-height: 80px;
  word-break: break-word;
  padding: 15px;
  border: 5px solid var(--orange);
  font-size: 2rem;
  text-align: center;

#animation-container {
  margin: auto;
  max-width: 300px;

.animation-frame {
  margin: 250px auto 0;
  padding: 15px 10px;
  border: 5px solid var(--orange);
  font-size: 1.2rem;
  text-align: center;

@media screen and (min-width: 500px) {
  .input-container {
    flex-direction: row;

  #result {
    max-width: 460px;
/* file: script.js */
const numberInput = document.getElementById("number-input");
const convertBtn = document.getElementById("convert-btn");
const result = document.getElementById("result");

const decimalToBinary = (input) => {
  if (input === 0) {
    return "";
  } else {

// User Editable Region

    return (decimalToBinary(Math.floor(input / 2)) + input % 2);

// User Editable Region


const checkUserInput = () => {
  if (!numberInput.value || isNaN(parseInt(numberInput.value))) {
    alert("Please provide a decimal number");

  numberInput.value = "";

convertBtn.addEventListener("click", checkUserInput);

numberInput.addEventListener("keydown", (e) => {
  if (e.key === "Enter") {

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Challenge Information:

Learn Recursion by Building a Decimal to Binary Converter - Step 69

return (decimalToBinary(Math.floor(input / 2)) + input % 2);

Of course, I don’t understand what is needed here, but the code doesn’t work as always

You appear to have created this post without editing the template. Please edit your post to Tell us what’s happening in your own words.

Please talk to us about how the instructions or error message is confusing. Thanks

After calling decimalToBinary() use the addition operator (+), should this be written on another line? Or after the function to the end of the line - it’s also unclear which line? not everything is clear here

You have to read the whole sentence together

After your call to decimalToBinary(), use the addition operator (+) to concatenate the remainder of input divided by 2 to the end of the string your recursive function returns.

You are modifying what is returned from the function, so the concatenation has to be part of the return statement.

Also, wrap the operation in parentheses.

Then don’t forget this part.

I also can’t calculate in the same way as in this example, if you take 8 / 2 = 4, you get 4 that must be divided by with a remainder of 2, then you get 0.042, but in program 1000, who knows how it all works?

I don’t understand your question.

This works with the / sign.

I want to understand how the result is obtained, how is it calculated?

Which result are you talking about?

For example, I enter 8 as input and the result is 1000, how does this happen?

Did you fix the code for this step yet? Its not possible to answer your question unless you’ve correctly followed the instructions for this step.