Yes, the rules of scientific notation are:
1. All non-zero digits are significant
2. Zeros in between non-zeros are significant.
3. Zeros to the left of the first non-zero number are NOT significant.
4. Zeros to the right of non-zero numbers are significant IF a decimal point is present.
P.S: if you need help with sig fig rounding, let me know.
Answer:
11, 17, and 28.
Step-by-step explanation:

Lowest number is 
Median is 
Highest number is 

Because 3/6 is equal to 1/2.
You multiply the 1 (in 1/2) by 3, and the 2 (in 1/2) by 3 to get 3/6. You need to have a common denominator, and 6 was the common denominator.