---
id: 5ddb965c65d27e1512d44dab
title: Part 18
challengeType: 0
isBeta: true
---
## Description
The `reduce()` method takes a callback function with at least two arguments, an accumulator and a current value:
`function(accumulator, currentValue) { /* code to run */ }`
or using arrow functions:
`(accumulator, currentValue) => { /* code to run */ }`
Insert the above callback function as an argument in the `.reduce()` method.
## Instructions
## Tests
```yml
tests:
- text: See description above for instructions.
testString: assert( code.replace(/\s/g, '').match(/reduce\(\(accumulator\,currentValue\)\=\>\{\/\*codetorun\*\/\}\)/) );
```
## Challenge Seed
```html
```
### Before Test
### After Test
```html