Give three different examples which satisfy the following:
$a × b ≡ 0 \pmod n$ but $a ≢ 0 \pmod n$ and $b ≢ 0 \pmod n$.
Example 1
$a = 2, b = 3, n = 6$ gives $2 \times 3 \equiv 0 \pmod 6$ but $2 \not \equiv 0 \pmod 6$ and $3 \not \equiv 0 \pmod 6$.
Example 2
$a = 2, b = 5, n = 10$ gives $2 \times 5 \equiv 0 \pmod {10}$ but $2 \not \equiv 0 \pmod {10}$ and $5 \not \equiv 0 \pmod {10}$.
Example 3
$a = 3, b = 5, n = 15$ gives $3 \times 5 \equiv 0 \pmod {15}$ but $3 \not \equiv 0 \pmod {15}$ and $5 \not \equiv 0 \pmod {15}$.