Question

find two different ways to show how you know either 3/4 is greater than 2/3

Answer 1

You can change them into fractions with the same denominator: multiply 3/4 by 3 and 2/3 by 4

3/4 = 9/12
2/3 = 8/12

You could also convert them to decimals. 
3/4 = 0.75
2/3 = 0.667

3/4 is greater than 2/3