How do you this? ? scientific notation

So Scientific Notation is a "simplified version" of a number. For example, is your number is 2,345, the scientific notation would be 2.345 * 10³. 

If it was 0.023, then the scientific notation would be 2.3 * 10^-2. 

Scientific notation is found by moving the decimal place to the left or right, until only one digit is left to the left of the decimal; it has to be greater than 1, but less than ten. If you move the decimal place to the right, it's a negative power of 10. If you move it to the left, it is a positive power of 10.

Hope this helps!

The first one, i believe, would be correct. all the others have one thing in common, and that's that they have repeating numbers. in the second one, x and y have repeating 6's and 3's, and in the third, x and y have repeating 6's as well. in the last one, there are repeating 3's. the first one has no repeating numbers.