Simplify $r + r$?

Hint: This question is a mathematical equation which is a combination of both numerical values and alphabets, these types of mathematical expressions are called algebraic expressions. In this question we have to simplify the given expression by taking a common term i.e., $r$ and then multiplying the number with the variable then we will get the required result.

Complete step by step answer:
An algebraic expression is a mathematical term that consists of variables and constants along with mathematical operators (subtraction, addition, multiplication, etc.).
Simplifying an algebraic expression means writing it in the most compact or efficient manner, without changing the value of the expression. This mainly involves collecting like terms, which means that we add together anything that can be added together.
Given expression is $r + r$,
Now taking common from both the terms we get,
$ \Rightarrow r\left( {1 + 1} \right)$ ,
Now simplifying we get,
 $ \Rightarrow r\left( 2 \right)$,
Now multiplying the terms we get,
 $ \Rightarrow r \times 2 = 2r$,
So, the simplified form is $2r$ .
The simplified form of the given expression $r + r$ will be equal to $2r$

Note: To evaluate an algebraic expression, you have to substitute a number for each variable and perform the arithmetic operations. If we know the value of our variables, we can replace the variables with their values and then evaluate the expression. To simplify any algebraic expression, the following are the basic rules and steps:
• Remove any grouping symbol such as brackets and parentheses by multiplying factors.
• Use the exponent rule to remove grouping if the terms are containing exponents.
• Combine the like terms by addition or subtraction.
• Combine the constants.