3367 Multiplied by 2-Digit Number

Theorem
In order to multiply $3367$ by a $2$-digit integer $\sqbrk {xy}$:


 * divide the $6$-digit integer $\sqbrk {xyxyxy}$ by $3$.

Proof
We have that:
 * $10101 = 3367 \times 3$

Then:
 * $10101 \times \sqbrk {xy} = \sqbrk {xyxyxy}$

The result follows.