The fourth and fifth
156569
The first and (the) second chapter(s) are difficult - which is correct?
143615
Can you construct a field with 4 elements?
15003
Pythagorean Quadruples:
35326
There are infinitely many $N$ such that $\frac{N}{2}$ is a perfect square, $\frac{N}{3}$ is a perfect cube, and $\frac{N}{5}$ is a perfect fifth power
90433
Isomorphisms between $(\mathbb Z_4,+)$ and $(U_5,*)$
104126
Challenging Chain Wild Draw Four's
50785
Galois group of $x^4-5$
142401
Where's the problem in this equation? Resulting in $4 = 5$
133937
Find the four digit number?
54794
British Olympiad; Combinatorics Recursion
61871
Formula for the $n$th term of $1, 2, 2, 3, 3, 3, 4, 4 ,4, 4, 5, ...$
152577
Proving $4^n > n^4$ holds for $n\geq 5$ via induction.
36691
Parameters on $SU(4)$ and $SU(2)$
96344
Combination with repetitions.
26138
Atiyah Macdonald Exercise 5.22
71067
Group differences on a five point Likert item
73105
Chapter 5: Are there multiple Endings?