Transcript Adding and Subtracting Whole Numbers - MATH GR 3-5

Adding and Subtracting Whole
Numbers
Benchmark


MA.2.A.2.1: Recall basic addition and related
subtraction facts.
MA.2.A.2.2: Add and subtract multi-digit whole
numbers through three digits with fluency by using a
variety of strategies, including invented and standard
algorithms and explanations of those procedures.
Objectives


Review of basic addition facts and related subtraction
facts.
Develop fluency with multi-digit addition and subtraction.
Sample Problems
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One day Juliana swam 4 laps. The next day she swam 3
more laps. How many laps did she swim altogether?
Nicole made a necklace. She used 13 red beads. She
used 28 blue beads. How many beads did she use
altogether?
There are 24 muffins in all. 15 muffins are on the plate.
How many muffins are not on the plate?
What is Addition?
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Addition is just a final count of numbers or items.
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The result of an addition is called the “sum.”
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Example: 3 + 4
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This is the addition of 3 and 4 or 3 plus 4
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Addition is represented as shown:
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We can count on to get the sum
3  4, 5, 6, 7
so the sum is 7
4
3
+4
Examples : Write the sums
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5 + 4 = ___
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4 + 5 = ___
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8 + 2 = ___
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2 + 8 = ___
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7 + 0 = ___
Word Problem
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Roger build 4 toy airplanes. Then he builds 3 more toy
airplanes. How many toy airplanes does he build
together?
Make-A-Ten Strategy
Think:
9 10
1
+ 4 +3
13
+
-
Try This!
9+4=
The answer is:
10 + 3 = 13
Subtraction Facts
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Subtraction is removing some objects from a group.
The meaning of 5 – 3 = 2 is "Three objects are taken
away from a group of five objects and two objects
remain".
Examples:
6-2=4
9-3=6
Subtraction Example
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Example: 8 - 3
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This is the subtraction of 3 from 8 or 8 minus 3
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Subtraction is represented as shown:

We can count down to get the difference
8  7, 6, 5
so the difference is 5
3
8
-3
Relationship between Addition and
Subtraction
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There is an inverse relationship between addition and
subtraction.
If a math fact is considered, for example 3 + 7 = 10.
Then the following are also true:
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10 - 3 = 7
10 - 7 = 3
Similar relationships exist for subtraction, for example
10 - 3 = 7. Then the following are also true:
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3 + 7 = 10
7 + 3 = 10
Review Examples
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Sierra ate three cereal bowls in the morning. She ate the
same number of bowls in the afternoon. How many
bowls did she ate altogether?
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Erin and Chase played many games of checkers. Erin won
11 games. Chase won 7 games. How many games did
Erin win than Chase?
Let’s add large numbers.
12 and 34
12
+ 34
Line up numbers
Line up the digits on top of each
other starting with the number
on the right (the rightmost digit,
which is called the “ones” place.)
Let’s add large numbers.
12 and 34
Line up numbers
12
+ 34
6
Line up the digits on top of each
other starting with the number
on the right (the rightmost digit,
which is called the “ones” place.)
Then add the numbers that
are on top of each other like
you normally would add
numbers.
Let’s add large numbers.
12 and 34
Line up numbers
12
+ 34
6
Line up the digits on top of each
other starting with the number
on the right (the rightmost digit,
which is called the “ones” place.)
Then add the numbers that
are on top of each other like
you normally would add
numbers.
Let’s add large numbers.
12 and 34
12
+ 34
46
Line up numbers
Line up the digits on top of each
other starting with the number
on the right (the rightmost digit,
which is called the “ones” place.)
And do the same for the
other column of numbers.
Adding larger numbers...
You may have to “carry” numbers to the
next column of numbers being added if
the first column is over 9.
231
+459
Adding larger numbers...
You may have to “carry” numbers to the
next column of numbers being added if
the first column is over 9.
231
+459
0
Since 9+1=10, we will write the
last digit of 10 (the zero) and
“carry” the one above the 3 to
the left to add it.
Adding larger numbers...
You may have to “carry” numbers to the
next column of numbers being added if
the first column is over 9.
1
231
+459
0
Since 9+1=10, we will write the
last digit of 10 (the zero) and
“carry” the one above the 3 to
the left to add it.
Adding larger numbers...
You may have to “carry” numbers to the
next column of numbers being added if
the first column is over 9.
1
231
+459
0
Now we will add the 3 and 5,
and also the 1 since it was
carried over.
Adding larger numbers...
You may have to “carry” numbers to the
next column of numbers being added if
the first column is over 9.
1
231
+459
90
Now we will add the 3 and 5,
and also the 1 since it was
carried over. 5+3+1=9 We do
NOT need to carry here.
Adding larger numbers...
You may have to “carry” numbers to the
next column of numbers being added if
the first column is over 9.
1
231
+459
90
Now we will add the 2 and 4
that in the far left column.
Adding larger numbers...
You may have to “carry” numbers to the
next column of numbers being added if
the first column is over 9.
1
231
+459
690
Now we will add the 2 and 4
that in the far left column.
2+4=6
With some practice, you will be able to
successfully add positive whole numbers!
This will be useful in all aspects of this
class AND in your everyday life.
Let’s look at a real-world example...
You graduated from Broward College!!!!
As some of your graduation gifts, you receive gifts
from family and friends with the values of
$50, $129, $78, and $23.
What is the total value of these gifts?
You will simply need to ADD all
of those numbers up to get the
total.
5 0
1 2 9
7 8
+
2 3
0
Keep in mind to line up
the places, add each column,
and carry if the number
has more than one digit!
0+9+8+3=20
2
5 0
1 2 9
7 8
+
2 3
0
Keep in mind to line up
the places, add each column,
and carry if the number
has more than one digit!
2+5+2+7+2=18
2
1
5 0
1 2 9
7 8
+
2 3
8 0
Keep in mind to line up
the places, add each column,
and carry if the number
has more than one digit!
1+1=2
2
1
5 0
1 2 9
7 8
+
2 3
2 8 0