addition algorithms s. matthews. partial-sums method for addition add from left to right and column...
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Addition Algorithms
S. Matthews
Partial-Sums Method for Addition
Add from left to right and column by column.
The sum of each column is recorded on a separate line.
The value of each digit is determined by its place in the numeral.
Let’s practice the value of digits for Partial-Sums.
In the problem 23 + 45, we first
add the 2 and 4.
However, the 2 is worth 2 tens,
and the 4 is worth 4 tens. So we
say 20, not 2; and 40, not 4.
In the problem 23 + 45, we first
add the 2 and 4.
However, the 2 is worth 2 tens,
and the 4 is worth 4 tens. So we
say 20, not 2; and 40, not 4.
Let’s practice the value of digits for Partial-Sums.
Your turn.
What do we say when
adding the hundred’s
place for 376 + 832?
Your turn.
What do we say when
adding the hundred’s
place for 376 + 832?
You’ve got it!
We say 300, n
ot 3; a
nd
800, not 8
.
What is th
e sum of th
e
100’s place
?
You’ve got it!
We say 300, n
ot 3; a
nd
800, not 8
.
What is th
e sum of th
e
100’s place
?
Can’t fool you!
In 376 and 832, the 3 is
worth 300, and the 8 is worth
800.
300 + 800 is 1,100 or eleven
hundred.
Can’t fool you!
In 376 and 832, the 3 is
worth 300, and the 8 is worth
800.
300 + 800 is 1,100 or eleven
hundred.
Let’s practice the value of digits for Partial-Sums.
Let’s continue.
What do we say when
adding the tens place for
376 + 832?
Let’s continue.
What do we say when
adding the tens place for
376 + 832?
That’s rig
ht!
We say 70, n
ot 7; a
nd 30,
not 3.
What is th
e sum of th
e 10’s
place?
That’s rig
ht!
We say 70, n
ot 7; a
nd 30,
not 3.
What is th
e sum of th
e 10’s
place?
Can’t fool you!
In 376 and 832, the 7 is
worth 70, and the 3 is worth
30.
70 + 30 is 100 or ten tens.
Can’t fool you!
In 376 and 832, the 7 is
worth 70, and the 3 is worth
30.
70 + 30 is 100 or ten tens.
Take a look at the steps for
addition using the Partial-
Sums Method.Then we’ll practice the
method some more.
Take a look at the steps for
addition using the Partial-
Sums Method.Then we’ll practice the
method some more.
398 + 435
Add the 100’s: 300 + 400 =
+ 13
Add the 10’s: 90 + 30 =
Add the 1’s: 8 + 5 =
Find the total
120
700
833
Now, you try the Partial- sums method using the numbers we practiced.
Now, you try the Partial- sums method using the numbers we practiced.
376 + 832
Add the 100’s: 300 + 800 =
+ 8
Add the 10’s: 70 + 30 =
Add the 1’s: 6 + 2 =
Find the total
100
1100
1, 208
You are good!
Let’s try just one more.
You are good!
Let’s try just one more.
479 + 285
Add the 100’s: 400 + 200 =
+ 14
Add the 10’s: 70 + 80 =
Add the 1’s: 9 + 5 =
Find the total
150
600
764
Excellent! I know you’ve got the hang
of it.
Don’t forget, in the Partial-Sums method for
addition, you:
• add the 100’s,
• add the 10’s,
• add the 1’s.
• Then add the sums you just found.
(the partial sums)
Excellent! I know you’ve got the hang
of it.
Don’t forget, in the Partial-Sums method for
addition, you:
• add the 100’s,
• add the 10’s,
• add the 1’s.
• Then add the sums you just found.
(the partial sums)
Keep practicing.
Peace!
Keep practicing.
Peace!