186,000 in scientific notation is:
1.86 x 10^5
When writing in scientific notation, the first number is any number less than 10. For the exponent, it is however many places the decimal point has been moved over. If it is positive, the number is large, you move the decimal over to the right. If it is negative, the number is smaller, you move the decimal over to the left.
In 186,000, you use 1.86 since it is less than 10. Now, you count however many places the decimal has been moved over from this number to make 186,000. In this case, it is 5 places, so that is the exponent.