190 likes | 264 Views
How are - 11 + 9 and 9 + (- 11) related? . In this lesson you will learn to demonstrate the commutative property of addition by using a number line. What’s an integer?. Integers include positive and negative whole numbers as well as 0. ...- 3, -2, -1, 0, 1, 2, 3 . Non-Examples:.
E N D
In this lesson you will learn to demonstrate the commutative property of addition by using a number line.
What’s an integer? Integers include positive and negative whole numbers as well as 0. ...-3, -2, -1, 0, 1, 2, 3 ... Non-Examples: -5.2 0.28 -9.9 4
What’s a number line? Increasing in Value Decreasing in Value Negative Numbers Positive Numbers
What’s addition? Addition is the process of joining two groups. 7 + 11 = 18 addend sum addend
Re-ordering the addends in an addition problem without re-ordering the signs. -11 11 + 9 9 - + Commutative Property
Re-ordering the addends in an addition problem without re-ordering the signs. -11 + 9 = - 11 9 - +
Re-ordering the addends in an addition problem without re-ordering the signs. -11 -11 + 9 9 ( ) ( ) +
Re-ordering the addends in an addition problem without re-ordering the signs. -11 + 9 = -11 ( ) ( ) 9 + Commutative Property
Commutative Property 2 + 6 2 6 8 6 + 2 6 2 8
Commutative Property -3 + (-4) -4 -3 -7 -7 -4 + (-3) -3 -4
Commutative Property 9 -11 + 9 -11 -2 -2 -11 9 + (-11) 9
In this lesson you learned to demonstrate the commutative property of addition by using a number line.
Show that 14 + (-9) is equal to -9 + 14. 14 + (-9) -9 + 14
Demonstrate that -6 + (-8) has the same value as -8 + (-6). -6 + (-8) -8 + (-6)
Use Cuisenaire rods to represent integers 1-10. Model addition problems that show the commutative property by laying the rods on a number line. These rods represent 8 + (-5) and -5 + 8. Both sums are positive 3!
The commutative property of addition is sometimes called the order property. • Use the commutative property to rearrange these addition expressions so you can add them mentally. (Hint: Try to make sets of ten.) • -15 + 28 + (-5) • -99 + 17 + 3 + (-1) • 74 + 12 + (-4) + 5
Partner Game: • First partner writes an integer addition problem for the second partner. • The first partner solves the original problem on her own paper. The second partner switches addends using the commutative property and solves the equivalent problem on his paper. • Both partners compare their answers.
Which expression has the same value as -13 + 7? A) 7 + (-13) B) 13 + (-7) C) -13 + (-7) D) -7 + 13 Which expression has the same sum as -9 and -2? A) 2 + 9 B) 2 + (-9) C) 9 + 2 D) -9 + (-2