Question 16
We call a positive integer *quadratic* if every two adjacent digits form a square number. For example, the number $364$ is quadratic because both $36$ and $64$ are squares.
How many digits does the largest quadratic number have?
A) $2$
B) $3$
C) $4$
D) $5$
E) $6$
How many digits does the largest quadratic number have?
A) $2$
B) $3$
C) $4$
D) $5$
E) $6$