Alright!
Three Fourths is 3/4.
So our numbers are...
3/4, -7/10, -3/4, 8/10
We'll need a common denominator to compare the fractions. A common denominator is simply a number which they are all divided by.
So! The one that jumps out the most is 40, because it is the lowest number that both 10 and 4 are divisible by.
In order to get a common denominator you must multiply it by that multiple.
3/4 * 10/10 = 30/40
-7/10 * 4/4 = -28/40
-3/4 * 10/10 = -30/40
8/10 * 4/4 = 32/40
Larger negative answers are smaller. Think of it in terms of a number line. As you go to the left the negative numbers get bigger and bigger, and thus smaller and smaller.
Least to greatest would look like this:
-30/40, -28/40, 30/40, 32/40