Question

Find the GCD:

(10) 777, 315, 588

Answer 1

$\begin{array}{cc}3& 777\\ 7& 259\\ 37& 37\\ & 1\end{array}$
⇒ 777 = 3 × 7 × 37

$\begin{array}{cc}3& 315\\ 3& 105\\ 5& 35\\ 7& 7\\ & 1\end{array}$
⇒ 315 = 3 × 3 × 5 × 7

$\begin{array}{cc}2& 588\\ 2& 294\\ 3& 147\\ 7& 49\\ 7& 7\\ & 1\end{array}$
⇒588 = 2 × 2 × 3 × 7 × 7

∴ GCD = 3 × 7 = 21