# Whole Number Addition and Subtraction Contributed by: Numbers
 Addition is just a final count of numbers or
items.
 Also called the “sum.”
12 and 34 Line
Line upup
the digits on top of
each other starting with
numbers the number on the right
(the rightmost digit, which
is called the “ones” place.)
12
+ 34
12 and 34 Line
Line upup
the digits on top of
each other starting with
numbers the number on the right
(the rightmost digit, which
is called the “ones” place.)
12 that are on top of each
other like you normally
+ 34
12 and 34 Line
Line upup
the digits on top of
each other starting with
numbers the number on the right
(the rightmost digit, which
is called the “ones” place.)
12 that are on top of each
other like you normally
+ 34
12 and 34 Line
Line upup
the digits on top of
each other starting with
numbers the number on the right
(the rightmost digit, which
is called the “ones” place.)
And do the same for the
12 other column of
numbers.
+ 34
You may have to “carry”
numbers to the next column of
numbers being added if the first
column is over 9.
231
You may have to “carry”
numbers to the next column of
numbers being added if the first
column is overSince9.9+1=10, we will
write the last digit of 10
231 (the zero) and “carry” the
one above the 3 to the
0
You may have to “carry”
numbers to the next column of
numbers being added if the first
1
column is overSince9.9+1=10, we will
write the last digit of 10
231 (the zero) and “carry” the
one above the 3 to the
0
You may have to “carry”
numbers to the next column of
numbers being added if the first
1
column is over 9.
Now we will add the 3
231 and 5, and also the 1
since it was carried over.
0
You may have to “carry”
numbers to the next column of
numbers being added if the first
1
column is over 9.
Now we will add the 3
231 and 5, and also the 1
since it was carried over.
5+3+1=9 We do NOT
+459 need to carry here.
90
You may have to “carry”
numbers to the next column of
numbers being added if the first
1
column is over 9.
Now we will add the 2
231 and 4 that in the far left
column.
90
You may have to “carry”
numbers to the next column of
numbers being added if the first
1
column is over 9.
Now we will add the 2
231 and 4 that in the far left
column.
2+4=6
690
14. With some practice, you will be
whole numbers!
This will be useful in all aspects of
this class AND in your everyday
Let’s look at a real-world
15. You graduated from Broward College!!!!
gifts from family and friends with the values
of
\$50, \$129, \$78, and \$23.
What is the total value of these gifts?
16. 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
17. Keep in mind to line up
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
18. Keep in mind to line up
and carry if the number
has more than one digit!
2+5+2+7+2=18
2
5 0
1
1 2 9
7 8
+ 2 3
8 0
19. Keep in mind to line up
and carry if the number
has more than one digit!
1+1=2
2
5 0
1
1 2 9
7 8
+ 2 3
2 8 0
20. 2
1
5 0
1 2 9
7 8
+ 2 3
28
You got \$280
Congratulations!!!
21. Other things, you need to know…
 When: (a + b) + c = a + (b + c)
 When: a + b= b + a
 When: a + 0= a
22. Other ways to perform additions
We used the round to the nearest 10
and 3 digit numbers
How can we mentally calculate 23 + 29?
23. What about a blank number line
How do we mentally calculate 23 + 29?
23 +29 is the same as 23+30-1
+30
52
53
23
-1
=23 + 30 – 1
=53 – 1
=52
24. “Joining up our thinking” Mapping
the partitioning strategy to our
54 + 38 54 + 38
50 + 30 +4 +8 50 + 30 +4 +8
54
+ 38 Partitioning:
80 What is 50 + 4
12 + 30 + 8
happening
80 Partitioning: 80 +12
10
in our mind
What is when we
2 = 92
happening use this
92
in our mind jotting?
when we
use this
jotting?
25.
26. What is Subtraction?
Subtracting whole
numbers is the inverse
whole numbers.
27. Subtractions with one digit
are usually fairly easy.
Things start getting
complicated when you
have more than one digit
and you cannot remove
the number at the bottom
from the number on top
such as when doing 85 − 8
28. Since you could not remove 8 from 5,
you borrowed a ten from 8 tens and
add that to 5 to make it 15
29. You can also write the problem without the tens and the
ones to make it look simpler as illustrated below
30. Another example
5424
- 756
Always start
with the
ones.
31. Step #1
Borrow a 10 from 2 tens
The problem becomes
32. Step #2
Borrow 1 hundred from 4 hundreds. 1
hundred = 10 tens. Then add 10 tens
to 1 ten to make it 11 tens
33. Step #3
Borrow 1 thousand from 5 thousands. 1 thousand =
10 hundreds. Then add 10 hundreds to 3 hundreds
to make it 13 hundreds
Then, just subtract now since all numbers at the
bottom are smaller than the number on top
34. Let’s Try Some!
7 17 2 12
4,987 3,230
- 2,158 - 320
2, 8 2 9 1, 9 1 0