+1556 Let $a$ be an integer such that $a \equiv 5 \pmod{7}$. Find the value of $a + 1 \pmod{7}$. Express your answer as a residue between $0$ and the modulus.
+1950 We have
a≡5(mod7)a+1≡5+1(mod7)a+1≡6(mod7)
Thus, the answer is 6.
Testing numbers like
5,12,19,26,33, they all satisfy the equation we are given.
Thanks! :)
