1. **State the problem:** Calculate the result of the subtraction $245879 - 987542$. 2. **Formula used:** Subtraction of integers is performed by subtracting the second number from the first: $$a - b$$ where $a = 245879$ and $b = 987542$. 3. **Perform the subtraction:** Since $245879 < 987542$, the result will be negative. 4. Calculate the difference ignoring the sign: $$987542 - 245879 = 741663$$. 5. Therefore, the final answer is $$245879 - 987542 = -741663$$. This means subtracting a larger number from a smaller number results in a negative number, and the magnitude is the difference between the two numbers.