Which list of numbers is in order from least to greatest?
3/6 3/10 3/7

The list of numbers from least to greatest is 

3/10 , 3/7, 3/6

This is because the numerator stays the same across all three of these fractions.  However, the denominator is changing, and this proves to be a large difference.  

Think about it this way: If you cut a pie into ten pieces, then those slices are going to be smaller than if you cut the pie into seven or six pieces.

The answer would be 3/10, 3/7, 3/6. 
This is because if you convert each of these into percentages you can find the answer very easy. 3/6 is obviously exactly half so that would be 50%. 
3/10 is split into tenths so 3 of those would be 30%. 
3/7 needs to be divided so 3 divided by 7 is equal to 43%. 
The lowest is the 30% or the 3/10. 
The middle number would be 43% or 3/7. 
The highest number is 50% or 3/6. 
It says to order them from least to greatest so take the lowest which is 3/10 then put the middle number which is 3/7 then the highest which is 3/6. 
Your final answer is: 3/10, 3/7, 3/6.