Column Addition
Addition
Column addition allows people to work with the place-value columns in
any order. It also allows them to write both digits of each partial answer
directly underneath the appropriate column and then, if necessary, to go
back and adjust the partial answers to find the final answer.
Many students find this algorithm very natural—and instructive.
Build Understanding
Using page 13, explain that with this method of adding, students will add
the digits in each column in any order, write individual place-value answers
as they go, and then, if necessary, go back and adjust those partial answers
to find the final answer. Use questions like the following to guide students
through the examples:
• Which two numbers will you begin with? (It doesn’t matter. The columns
can be added in any order.)
• Where do you write the sum for each column? (in the same column
directly beneath the digits being added)
• How do you adjust the place-value answers? (If the sum in a column has
two digits, write down the ones digit and add a 1 to the answer in the
column to the left.)
While working through Example 1, model appropriate place-value language:
“2 hundreds plus 4 hundreds are 6 hundreds; 6 tens plus 8 tens are 14 tens;
and 8 ones plus 3 ones are 11 ones. ... Now, we have 14 tens and since 10 tens
equal 1 hundred, we have 7 hundreds and 4 tens. ... We have 11 ones and
since 10 ones equal 1 ten, we have 5 tens and 1 one.” (When working through
Example 2, point out that another name for “14 hundreds” is “1 thousand,
4 hundreds.”)
Page 13
Answer Key
Check Understanding
1. 1,275
Make sure students understand that the final sum in Example 1 is 751. If
necessary, work through additional examples on the board. When you are
reasonably certain that most of your students understand the algorithm,
assign the “Check Your Understanding ” exercises at the bottom of page 13.
(See answers in margin.)
2. 821
3. 582
4. 913
5. 1,082
Copyright © Wright Group/McGraw-Hill
Error Alert To help students organize both their thinking and their
writing, encourage them to put extra space between the digits in each addend
and to draw vertical lines to separate the place-value columns.
6. 1,152
7. 2,626
8. 8,348
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Teacher Notes
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Name
Date
Time
Column Addition
2
+4
Example 1
Add the digits in each column.
If necessary, adjust the hundreds and the tens.
If necessary, adjust the tens and the ones.
→
→
→
6
7
7
9
+4
Example 2
Copyright © Wright Group/McGraw-Hill
Add the digits in each column.
If necessary, adjust the hundreds and the tens.
If necessary, adjust the tens and the ones.
→
→
→
6
8
Addition
Add one place-value column at a time. Write each
place-value answer directly beneath the problem.
Then go back and adjust each place-value answer,
if necessary, one column at a time.
8
3
14 11
4 11
5 1
6
9
7
5
13 15 12
14 5 12
1, 4 6 2
Check Your Understanding
Solve the following problems.
1. 511 + 764
2. 703 + 118
3. 303 + 279
4. 442 + 471
5. 453 + 629
6. 862 + 290
7. 1,859 + 767
8. 1,095 + 2,817 + 4,436
Write your answers on a separate sheet of paper.
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Student Practice
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