s18-13 Number theory

Problems

Name Solved / Tries Average tries Average tries to solve
A Factor-Free Tree 0/0 (0%) -- --
B How Many Digits? 37/196 (19%) 5.30 5.30
C I Hate The Number Nine 35/121 (29%) 3.46 3.46
D Blackboard Numbers 11/48 (23%) 4.00 3.73