Number Calculation and Digit Sum

Let the unknown number be represented by the variable '$x$'.

The problem statement translates to the following algebraic equation:

$ \frac{1}{3}x + 25 = 100 $

Solving the Equation

To find the value of the number '$x$', follow these steps:

• Subtract 25 from both sides of the equation:

  $ \frac{1}{3}x = 100 - 25 $

  $ \frac{1}{3}x = 75 $

• Multiply both sides by 3 to isolate '$x$':

  $ x = 75 \times 3 $

  $ x = 225 $

Calculating the Sum of Digits

The original number is 225.

To find the sum of its digits, add the individual digits together:

Sum = $ 2 + 2 + 5 $

Sum = $ 9 $