Download Lesson 2-1

Lesson 2-1
Algebra: Addition Properties and Subtraction Rules
1. Identify the property shown by 2 + 0 = 2.
0 is added to the number 2 and the sum is 2. This is the Identity Property of Addition.
2. Find 13 + 15 + 17.
You can use the Commutative Property and the Associative Property to add mentally.
13 + 15 + 17
13 + 17 + 15
Commutative Property
(13 + 17) + 15
Associative Property
(30) + 15
Add.
45
Add.
So, the sum is 45.
3. Find the missing number in 9 –
= 9.
When you subtract 0 from 9, the result is 9. So, the missing number is 0.