Python Program to Input a Number n and Compute n+nn+nnn

In this tutorial, we'll write a Python program to input a number n and compute the sum n + nn + nnn. For example, if n = 4, we calculate 4 + 44 + 444 = 492.

The key approach is to convert the number to a string and concatenate it to create the required patterns.

Example

Here's the complete program ?

n = int(input("Enter a value for n: "))
n_str = str(n)

# Create the patterns: nn and nnn
nn = n_str + n_str
nnn = n_str + n_str + n_str

# Calculate the sum: n + nn + nnn
result = n + int(nn) + int(nnn)

print(f"The computed value is: {result}")

Output

Enter a value for n: 4
The computed value is: 492

How It Works

The program follows these steps ?

• Take input from the user and convert it to an integer

• Convert the number to a string for easy concatenation

• Create nn by concatenating the string twice

• Create nnn by concatenating the string three times

• Convert the string patterns back to integers and sum them with the original number

• Display the final result

Alternative Approach Using Mathematical Formula

We can also solve this mathematically without string operations ?

n = int(input("Enter a value for n: "))

# Count digits in n
digits = len(str(n))

# Calculate nn and nnn mathematically
nn = n * (10**digits) + n
nnn = n * (10**(2*digits)) + n * (10**digits) + n

result = n + nn + nnn

print(f"The computed value is: {result}")
print(f"Breakdown: {n} + {nn} + {nnn} = {result}")

Output

Enter a value for n: 4
The computed value is: 492
Breakdown: 4 + 44 + 444 = 492

Comparison

Conclusion

String concatenation provides a straightforward solution to create the pattern n + nn + nnn. The mathematical approach offers better understanding of the underlying number structure and works efficiently for any digit length.