This mathematics lesson discusses the relationship between addition and subtraction. Students are asked to represent expressions using tape diagrams and use variables to write number sentences representing identities. The lesson evaluates expressions by adding and removing amounts from tape diagrams. It aims to demonstrate that adding a number is the same as subtracting its opposite, and vice versa, through visual diagrams and algebraic expressions.

1. Lesson 1
NYS COMMON CORE MATHEMATICS CURRICULUM
6•4
Lesson 1:The Relationship of Addition and Subtraction
Classwork
Opening Exercise
a.
Draw a tape diagram to represent the following expression:
b.
.
Write an expression for each tape diagram.
i.
ii.
Exercises
1.
Predict what will happen when a tape diagram has a large number of squares, some squares are removed, but then
the same amount of squares are added back on.
2.
Build a tape diagram with
squares.
a.
Remove
of them. Write an expression to represent the tape diagram.
b.
Add
c.
Evaluate the expression.
squares onto the tape diagram. Alter the original expression to represent the current tape diagram.
Lesson 1:
Date:
©2013CommonCore,Inc. Some rights reserved.commoncore.org
The Relationship of Addition and Subtraction
3/7/14
S.1
This work is licensed under a
Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License.
1

2. Lesson 1
NYS COMMON CORE MATHEMATICS CURRICULUM
3.
Write a number sentence, using variables, to represent the identities we demonstrated with tape diagrams.
4.
6•4
Using your knowledge of identities, fill in each of the blanks.
a.
_____
b.
c.
_____
____
d.
5.
_____
Using your knowledge of identities, fill in each of the blanks.
a.
_____
b.
c.
d.
_____
_____
_____
Lesson 1:
Date:
©2013CommonCore,Inc. Some rights reserved.commoncore.org
The Relationship of Addition and Subtraction
3/7/14
S.2
This work is licensed under a
Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License.
2

3. Lesson 1
NYS COMMON CORE MATHEMATICS CURRICULUM
6•4
Problem Set
1.
Fill in each blank
a.
_____
b.
c.
2.
_____
______
Why are the number sentences
Lesson 1:
Date:
©2013CommonCore,Inc. Some rights reserved.commoncore.org
and
called identities?
The Relationship of Addition and Subtraction
3/7/14
S.3
This work is licensed under a
Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License.
3