---
id: 5900f3fd1000cf542c50ff10
challengeType: 5
title: 'Problem 145: How many reversible numbers are there below one-billion?'
videoUrl: ''
localeTitle: 问题145：有多少可逆数字低于十亿？
---

## Description
<section id="description">一些正整数n具有sum [n + reverse（n）]完全由奇数（十进制）数字组成的属性。例如，36 + 63 = 99和409 + 904 = 1313.我们将这些数字称为可逆的;所以36,63,409和904是可逆的。 n或反向（n）中不允许前导零。 <p>有一千个可逆数字低于一千。 </p><p>有多少可逆数字低于十亿（109）？ </p></section>

## Instructions
<section id="instructions">
</section>

## Tests
<section id='tests'>

```yml
tests:
  - text: <code>euler145()</code>应该返回608720。
    testString: 'assert.strictEqual(euler145(), 608720, "<code>euler145()</code> should return 608720.");'

```

</section>

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

<div id='js-seed'>

```js
function euler145() {
  // Good luck!
  return true;
}

euler145();

```

</div>



</section>

## Solution
<section id='solution'>

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