Key Concepts

• Addition Notation To describe addition, we can use symbols and words.
Operation Notation Expression Read as Result
Addition $+$ $3+4$ three plus four the sum of $3$ and $4$
• The sum of any number $a$ and $0$ is the number.
• $a+0=a$
• $0+a=a$
• Changing the order of the addends $a$ and $b$ does not change their sum. $a+b=b+a$ .