Scientific notation is a way that makes it possible to express too large or too small numbers, being written in the decimal form, and all the extra numbers will be reduced to a number between 1 and 9.9 multiplied by 10 raised to some power
In the case of the question we have the addition of two numbers in scientifc notation
Instead of being 12600 + 25000, it is 1.26*10^4 + 2.50*10^4, which is equal to
37600 or in scientific notation = 3.76*10^4