(1.02 x 10^8) + (9.4 x 10^7) + (6.8 x 10^7) i need

2.64 × 10⁸  

Step-by-step explanation:

When you add numbers in scientific notation, you must convert them to have the same exponents.

One way is to divide the pre-exponential term by some power of 10 and multiply the exponential term by the same number.

    1.02 × 10⁸              = 1.02 × 10⁸

+ (9.4/10¹) × (10⁷×10¹) = 0.94 × 10⁸

+ (6.8/10¹) × (10⁷×10¹) = 0.68 × 10⁸

                     TOTAL = 2.64 × 10⁸