Scientific notation is used to write a larger number more easily. It is always written for integers as a x 10^b. So for to write 2,500 in scientific notation, find the answer for a and b. Step 1 is to find a, to do this move the decimal to the right of the first integer. So 2,500 will be 2.500. Next, to find b - count the number of places to the right of the decimal. There are three places to the right of the decimal. So a = 2.5 and b = 3, so the answer is 2.5 x 10^3.