Give three different examples which satisfy the following:
$a × b ≡ 0 \pmod n$ implies $a ≡ 0 \pmod n$ or $b ≡ 0 \pmod n$.
Example 1
$a =2, b =3, n = 2$ gives $2 \times 3 \equiv 0 \pmod 2$, and $2 = 0 \pmod 2$.
Example 2
$a =10, b =3, n = 5$ gives $10 \times 3 \equiv 0 \pmod 5$, and $10 = 0 \pmod 5$.
Example 3
$a =3, b =20, n = 10$ gives $3 \times 20 \equiv 0 \pmod 10$, and $20 = 0 \pmod 10$.