---
id: 645c81683d816b7b3a044143
title: Step 40
challengeType: 0
dashedName: step-40
---
# --description--
In the previous version of this function, you pushed the remainder of `input` divided by `2` to `binaryArray`. Then later you reversed and joined the entries into a binary number string.
But it would be easier to use string concatenation within the loop to build the binary string from right to left, so you won't need to reverse it later.
First, use the `remainder` operator (`%`) to set `binary` equal to the remainder of `input` divided by `2`.
# --hints--
You should set the value of `binary` within your `while` loop.
```js
assert.match(code, /while\s*\(\s*input\s*>\s*0\s*\)\s*\{[\s\S]+binary\s*=/);
```
You should set `binary` equal to the remainder of `input` divided by `2`.
```js
assert.match(code, /while\s*\(\s*input\s*>\s*0\s*\)\s*\{[\s\S]+binary\s*=\s*input\s*%\s*2\s*;?/);
```
# --seed--
## --seed-contents--
```html