Tia Rew

Adding and Subtracting Integers

Grade: 7th

 

Objectives: SWBAT use different methods to add and subtract integers, and find zero pairs

 

TEKS: 7.2c- use models, such as concrete objects, pictorial models, and number lines, to add, subtract, multiply, and divide integers and connect the actions to algorithms.

7.13d- select tools such as real objects, manipulatives, paper/pencil, and technology or techniques such as mental math, estimation, and number sense to solve problems.

 

Materials:

•    Overhead projector

•    White board

•    Two-color counters

•    Versailles

 

Introductory Activity: a riddle to solve

 

Focus: tell the students what they will be learning today

 

Relevancy: use the example of loosing yards in a football game, or owing someone money

 

Hot Question: (Ap)- Who else can think of a situation of when you would have a negative number?

 

Terms:

•    Integers- whole numbers and their opposites

•    Opposite Integers- two numbers that are the same distance form zero, but are on opposite sides of zero

•    Zero Pair- two opposite integers that subtract each other out

 

Hot Question: (K)- Who can tell me what a zero pair is in their own words and give me an example

 

Concept Discovery and Guided Practice:

•    Adding: if the signs are alike, add them and keep the same sign

If the signs are different, subtract and keep the sign of the biggest number

•    Subtracting: change the subtraction sign to addition

 

Hot Question: (K, C)- Does this problem look like the ones from before? How so?

Change the sign of the second number, this is called Add the Opposite

•    Use two-color counters to model adding and subtracting integers Red- negative numbers Yellow- positive numbers

Hot Question: (An)- How do you suppose we add and subtract integers on a number line?

 

•    Use a number line to do the same examples

 

Hot Question: (An)- How would I solve 6 - (-12) with two-color counters compared to 6 + (-12)?

 

Independent Practice:

•    Introduce the use of the versatiles

•    Have everyone draw for a problem on the worksheet to solve and then present to the class. When they are finish, they are to move their piece to the correct location

 

Evaluation:

•   As the students are working on their problem, walk around and monitor, and check for understanding, you might have to re-teach if the students are not grasping the concepts.

Closure:

 

Hot Question: (S)- We are going to make a two-tab book for adding and subtracting integers

 

•           Have the students create a two-tab book

•           One side with things to help them add integers

•           The other side with things to help them subtract integers

•           The homework is a set of questions with a helpful test taking tip

 

Hot Question: (C)- In your own words, how do we add and subtract integers?

 

Hot Question: (E)- How do we know when we are going to add or subtract the numbers?

 

Extension:

•   Challenge the students to add and subtract with a variable

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Adding and Subtracting Integers

 

Activity Title: ____________________                       Name: ________________________

Directions: Solve the equation using two-color counters and a basic mat.

 

1.  3 + (-1) =

 

2.  (-6) + 12 =

 

3.  (-4) + (-4) =                                              When the signs are the same you add them up

                                                                                          When the signs are different you

4.   (-6) – 12 =                                                                       subtract them down.

                                                                                                   Dillup

5.  11 – (-2) =                                                                             Dillup

 

6.  (-7) – (-2) =

 

7.  13 + (-15) =

 

8.  (-24) +17 =

 

9.  11 + (-2) =

 

10.  5 – 6 =

 

11.  19 – 23 =

 

12.  22- 5 =

 

 

 

 

 

 

 

A.   -2	B.   -1	C.   -4	D.   13	E.   17	F.   -7
G.   -18	H.   2	I.   -8	J.   9	K.   -5	L.   6

 

 

 

Adding and Subtracting Integers

 

1) Use colored tiles or sketch to find the sums of the following integers.

 

a) (+2) + (+3) =          _____             b) (+2) + (-9) =           _____

 

c) (-5) + (-2) =            _____             d) (-3) + (+8) =           _____

 

e) (+7) + (-7) =           _____             f) (0) + (-6) =               _____

 

 

2) Use colored tiles or sketch to find the differences of the following integers.

 

a) (+2) – (-3) =           _____             b) (+2) – (+9) =          _____

 

c) (-5) – (+2) =           _____             d) (-3) – (-8) =            _____

 

e) (+7) – (+7) =          _____             f) (0) – (+6) =              _____

 

3) Study the addition and subtraction sentences in question 1 and 2. Look for a pattern. How could you explain to another student, the steps to take in using addition to help with subtraction?

________________________________________________________________

 

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4) Use colored tiles or sketch to answer the following. Watch the signs.

 

a) (+4) + (-2) =           _____             b) (-4) – (-6) =            _____

 

c) (+7) – (+5) =          _____             d) (-7) + (-6) =            _____

 

e) (-6) + (+9) =           _____