To solve $10^5 + 10^5 + 10^5 + 10^5$, let's break it down step by step:

Step 1: Factor out $10^5$

$10^5 + 10^5 + 10^5 + 10^5 = 4 \cdot 10^5$

This is because adding $10^5$ four times is the same as multiplying $10^5$ by 4.

Step 2: Evaluate the answer options

The correct answer is J. $4 \cdot 10^5$.

Do you want a detailed explanation or further clarifications?

Related Questions:

1. What is the general formula for factoring repeated terms?
2. How would the solution change if there were $n$ repetitions of $10^5$?
3. How is $10^5$ expanded in decimal form, and what are its properties?
4. What happens if you add numbers with different exponents of 10, like $10^5 + 10^6$?
5. How is the concept of factoring out similar to distributing in algebra?

Tip:

When adding terms with the same base and exponent, factor out the common term to simplify the calculation.