Let $a, b \in \mathbb{R}$ each be a D993: Real number.

Then \begin{equation} \begin{split} (a + b)^6 = a^6 + 6 a^5 b + 15 a^4 b^2 + 20 a^3 b^3 + 15 a^2 b^4 + 6 a b^5 + b^6 \end{split} \end{equation}