Adding and Subtracting basic

Integers

Grade 3

The layout3rd grade Arizona State Standards

3.OA.83.MP.1, 3.MP.2, 3.MP.4, 3.MP.5

3.NBT.2

Part 1: The IntroPart 2: Do it together

Part 3: Bringing it back

Question of the Day: How can you use integers and number lines to solve equations?

Part 1:The Intro

What is an integer?

• Integers are any whole number named on a number line. (0,1,2,3).

• They also include numbers that are less than zero called Negative numbers which look like; -1, -2, -3.

• Integers do not include fractions or decimals.• Negative numbers are numbers that we will discuss

at another time but are important to acknowledge.

Using a number line

• To help understand integers we have used a variety of tools in the past, counting cubes, fingers, dots cards, hundred charts and number lines.

• Today we will use the number line to help solve our equations.

Number linesUsing a number line helps show how positive and

negative integers interact in order to solve an equation. For example: the equation 465- 33= x

465 is where we would start on the number line-33 is the integer we are taking away

X is the integer we are solving for

• Seeing this equation on a number line helps us to understand that by taking away 33, the difference is closer to the 0 point on the number line.

So what does that all mean?

http://www.slimber.com/index.php?image=integers-subtraction.g66435

(Hit play to watch)

When subtracting positive integers on a

number line, we move from the larger number

(minuend) and count back the number given

(subtrahend) to arrive at the difference.

Here is an example using subtraction an open number

line.

When adding positive integers on a number

line, we move from one number (addend) and

count forward the other number given (addend)

to arrive at the sum.

Here is an example using addition an open number

line.http://www.slimber.com/index.php?image=adding-integers.g66474

(Hit play to watch)

Moving closer to zeroWhen we subtract positive

integers from one another we are moving closer to zero on the

number line.Think of using a thermometer to

find the temperature:As the weather gets cooler the reading on the thermometer

becomes lower, closer to zero. As it gets warmer the reading moves up, away from zero. Just like integers

on a number line.

Part 2:Do it together

Try these….

Create an open number line to solve the following

equations:

a. 829 - 56= ____b. 1,125 - 251= ____c. 73 + 320= _____

d. 2,332 + 171= _____

How did you do?

a. 773b. 874c. 393

d. 2,503

Work it out

773 803 823 829

- 6-20- 30

1,1251,025900 925875874-100-100-25-25-1

73+20

93+100 +100+100

193 293 393

2,332+100

2,432+70

2,502+1

2,503

Part 3:Bringing it Back

What do you know about integers?

• Integers are whole numbers• They can be positive or

negative numbers• Integers can be used on a

number line• Adding moves the sum away

from zero• Subtracting moves the

difference closer to zero• Integers are not fractions or

decimals

Fun with IntegersCan you figure out

their mistakes?

http://teachertube.com/viewVideo.php?title=Abbot_and_Costello_Maths_Problem&video_id=3963

Finally!

Can you answer the Question of the day?

Question of the Day: How can you use integers and number lines to

solve equations?