# Convert Decimal Number to Binary Number

In this lesson, we will write the code to count the number of bits present for a given input.

## Introduction

Given a decimal number, continue dividing the number by 2 until it reaches either 0/1 and record the remainder at each step. The resulting list of remainders is the equivalent binary number for your decimal number.

**For example:**

```
Input: 125
Output: 1111101
```

Repeatedly do the modulo operation until `n`

becomes `0`

using

“

`%`

” and “`division`

” operations.

So, using the modulo and division method, we calculate the binary representation of a decimal number. Let’s represent the binary by considering the **remainder** column from **bottom to top.**

$(125)_{10}$ becomes $(1111101)_{2}$

The illustration below explains the process of counting the digits in an integer.

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