freeCodeCamp/curriculum/challenges/english/08-coding-interview-prep/project-euler/problem-206-concealed-square.english.md

---
id: 5900f43a1000cf542c50ff4d
challengeType: 5
title: 'Problem 206: Concealed Square'
---

## Description
<section id='description'>
Find the unique positive integer whose square has the form 1_2_3_4_5_6_7_8_9_0, where each “_” is a single digit.
</section>

## Instructions
<section id='instructions'>

</section>

## Tests
<section id='tests'>

```yml
tests:
  - text: <code>euler206()</code> should return 1389019170.
    testString: assert.strictEqual(euler206(), 1389019170, '<code>euler206()</code> should return 1389019170.');

```

</section>

## Challenge Seed
<section id='challengeSeed'>

<div id='js-seed'>

```js
function euler206() {
  // Good luck!
  return true;
}

euler206();
```

</div>



</section>

## Solution
<section id='solution'>

```js
// solution required
```
</section>