If you consider the each denominator, for the fraction to be greater than 1/2, then the numerator needs to be greater than 1/2 the denominator.
For example, with “something”/12: 6 is 1/2 of 12, so 6/12 is the same as 1/2. For a fraction of “something” / 12 to be greater than 1/2, the numerator needs to be greater than 6. 7/12 is.
With 5/12, 5 < 6, so 5/12 < 6/12, so 5/12 < 1/2.
With 5/10, half of 10 is 5, so 5/10 = 1/2
With 3/7, half of 7 is 3.5, so 3.5/7 is 1/2. Since 3<3.5, 3/7 < 1/2.
