What is the multiplicative equivalent to $\sum$?

Question

Suppose you wanted to simplify the expression $(1+a_{1})+(1+a_{2})+(1+a_{3})+...+(1+a_{n})$. To do this, you could express it as $\sum_{i=1}^{n} (1+a_{i})$.

However, what if you had the expression $(1+a_{1})(1+a_{2})(1+a_{3})...(1+a_{n})$. How would you simplify this in a similar way?

Answer 1

The product series symbol is Pi: $\quad\prod\limits_{i=1}^n (1+a_i)$

This and other mathematical symbols can be found here.

Answer 2

$$\prod_{j=1}^n(1+a_j)$$

The letter $\pi$ is for product, of course.