# Python Program to Find Sum of First and Last Digit

Given a positive integer N(at least contain two digits). The task is to write a Python program to add the first and last digit of the given number N.

**Examples:**

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Input:N = 1247

Output:8

Explanation:First digit is 1 and Last digit is 7. So, addition of these two (1 + 7) is equal to 8.

Input:N = 73

Output:10

**Method 1:** String implementation

- Take input in the form of String or typecast given input in String.
- Now pick the 0th index of the String and typecast it into Integer and store it in a variable.
- The same thing with the -1st index and also store in another variable.
- Now add these two variables and
- print them as an Output.

**Note: **We can access the first element of String using **string[0]** and the last element of String using **string[-1]**.

## Python3

`# We have a number` `number ` `=` `1247` ` ` `# We are type casting it in string` `number ` `=` `str` `(number)` ` ` `# Storing first and last digit in a variable` `# after type casting into Integer.` `first_digit ` `=` `int` `(number[` `0` `])` `last_digit ` `=` `int` `(number[` `-` `1` `])` ` ` `# Adding these two variables` `addition ` `=` `first_digit ` `+` `last_digit` ` ` `# Display our output` `print` `(` `'Addition of first and last digit of the number is'` `, ` ` ` `addition)` |

**Output:**

Addition of first and last digit of the number is 8

**Method 2: **Solve it using an integer

- We have given a positive Integer.
- After dividing by 10, store the remainder in a
**result**variable. - Continue the loop until the number becomes less than 9.
- Each time in the loop, divide the number by 10(integer division).
- After the end of the loop.
- Add the number in the
**result**variable. - Display the result variable as the output.

**Note: **Whenever we divide any number with 10, we get the last digit as the remainder. If we divide any number with 100, we get the last two-digit as the remainder.

## Python3

`# We have a number.` `number ` `=` `1247` ` ` `# Assigning last digit of the number in res` `# variable.` `res ` `=` `number ` `%` `10` ` ` `# Now, continue a loop until` `# the number becomes less than 9.` `while` `number > ` `9` `:` ` ` ` ` `# integer division of the number and reassigning` ` ` `# it.` ` ` `number ` `=` `number ` `/` `/` `10` ` ` `# Here, our number only contain one digit.` `# So, add this number in res variable.` `res ` `+` `=` `number` ` ` `# Now, display our output` `print` `(` `'Addition of first and last digit of number is'` `, res)` |

**Output:**

Addition of first and last digit of the number is 8

**Time Complexity: **O(n), where n is how many digits are there in the given number.