Dayna writes the integers $$1,2,3,4,5,6,7,8,9,10,11,12$$on a chalkboard, then she erases the integers from $1$ through $6$, as well as their multiplicative inverses $\pmod{13}$. What is the only integer Dayna does not erase?
Question:
Dayna writes the integers $$1,2,3,4,5,6,7,8,9,10,11,12$$on a chalkboard, then she erases the integers from $1$ through $6$, as well as their multiplicative inverses $\pmod{13}$. What is the only integer Dayna does not erase?
Answer:
Let's think step by step.

user
12
Dayna writes the integers $$1,2,3,4,5,6,7,8,9,10,11,12$$on a chalkboard, then she erases the integers from $1$ through $6$, as well as their multiplicative inverses $\pmod{13}$. What is the only integer Dayna does not erase?
train