Explanation:
"without finding equivalent fractions" is very hard, because you do exactly that either directly or indirectly when answering such a question.
a.
5/15, 3/4, 4/5
5/15 is much less than 1/2.
3/4 and 4/5 are both much larger than 1/2.
4/5 is much closer to 1/1 (the whole) than 3/4, as 4 out of 5 parts contains more of the whole than 3 it of 4 parts.
b.
5/11, 2/3, 6/7
like a. : 5/11 is less than 1/2.
2/3 and 6/7 are larger than 1/2.
6/7 is again much closer to 1/1 than 2/3 (6 parts of 7 vs. 2 parts of 3).
c.
3/50, 1/3, 2/5, 5/8, 3/4
3/50 is really small. much smaller than 1/3 and the rest.
for 1/3 to 2/5 we have to use equivalent fractions :
1/3 = 2/6
now 2/6 vs. 2/5 it is clear that 2 larger parts is bigger than 2 smaller parts (1/5 > 1/6).
but they are both smaller than 1/2.
between 5/8 and 3/4 (both larger than 1/2) we need to use again equivalent fractions :
3/4 = 6/8
clearly, 6/8 > 5/8
d.
3/10, 2/5, 4/7, 5/6, 7/8
3/10 and 2/5 are smaller than 1/2.
but between them we need again equivalent fractions :
2/5 = 4/10
clearly 4/10 > 3/10
4/7 is larger than 1/2 but still far from 1/1 (the whole).
5/6 and 7/8 are both closer to 1/1.
but for 5/6 a while 1/6 is still missing, while for 7/8 only a 1/8 is missing.
and because 1/6 > 1/8, 7/8 > 5/6.