$A=\bigg\{\sum_{i=1}^{\infty} \frac{a_i}{5^{i}}\ :\ a_i\in\{0,1,2,3,4\} \bigg\} \subset \mathbb{R}.$ Then which of the following are true
Let $A=\{\sum_{i=1}^{\infty} \frac{a_i}{5^{i}}:a_i=0,1,2,3$ or $4 \} \subset \mathbb{R}$. Then which of the following are true??