Add 7.3 × 10⁷ + 1.8 × 10⁷. From the answers selection below, which is the correct sum?

8.1 × 10⁷
9.1 × 10⁷
9.1 × 10¹⁴
9.1 + 10⁷

The correct sum is 9.1 × 10⁷.

To add numbers written in scientific notation, we need to make sure the exponents are the same.

In this case, we have:
7.3 × 10⁷
1.8 × 10⁷

Since the exponents are the same (both 10⁷), we can simply add the coefficients (numbers in front of the 10⁷).

So, 7.3 + 1.8 equals 9.1.

The sum of the two numbers in scientific notation is: 9.1 × 10⁷.

Therefore, the correct answer is: 9.1 × 10⁷.

To add numbers in scientific notation, you need to make sure the exponents are the same. Here's how you can add 7.3 × 10⁷ and 1.8 × 10⁷:

Step 1: Ensure both numbers have the same exponent by adjusting them accordingly. In this case, we can rewrite 1.8 × 10⁷ as 0.18 × 10⁸.

Step 2: Add the numerical values together. 7.3 + 0.18 = 7.48.

Step 3: Write the result in scientific notation, using the common exponent from Step 1. The result is 7.48 × 10⁷.

Therefore, the correct sum is 7.48 × 10⁷.