Tuesday, September 23, 2014

Addition Math Strategies

Below are some tips that might be helpful when your student brings home their work on Tuesday. We are focusing on two different types of addition. They are:  Partial-Sums and Column-Addition.

I have written out an example, and I have also attached a link to a video that will help explain the process as well. It was difficult to format the example for Column-Addition, so I attached a photo. The steps are colored in coordination with the actual work in the photo. If you have questions, let me know! I know this is a very different method, than many of us, including myself, grew up with. We are in this journey together! I have found these methods fantastic for teaching addition, and really help students make sense of addition. Enjoy!


Partial-Sums

The partial-sums method is used to find sums mentally or with paper and pencil. Here is the partial-sums method for adding 2-digit or 3-digit numbers:

Steps:
1.) Add the 100s
2.) Add the 10s
3.) Add the 1s
4.) Then add the sums you just found (the partial sums).


Example:

                                                                          46
                                                                        +37 
Add the 10s:                    40+30 ----------->       70
Add the 1s:                        6+  7 ----------->     +13
Add the partial sums       70+13 ----------->       83

                                                                                   233
                                                                                 +158
Add the 100s:                  200+100 -------->                300
Add the 10s:                      30+  50 -------->                  80
Add the 1s:                         3 +   8 --------->                +11
Add the partial sums:  300 + 80 + 11 ----->                391


Column-Addition 

The column-addition method can be used to find sums with paper and pencil, but it is not a good method for finding sums mentally.

Here is the column-addition method for adding 2-digit or 3-digit numbers.

1.) Draw lines to separate the 1s, 10s, and 100s places.
2.) Add the numbers in each column. Write each sum in its column.
3.) If there are 2 digits in the 1s place, trade 10 ones for 1 ten.
4.) If there are 2 digits in the 10s places, trade 10 tens for 1 hundred.

Example:

Add 248+187 using the column-addition method.

https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEihHfAFEWkAcutRYDBYno5-HZpqToTQ6eGT8WfvtXu6iyKvhgbS7MKHrXa47POhL-Tylaq-OiBw6-WFnIPM1XcVeLrrMUYay3wBvR9tult7ZIJ1D1PEKRuAFekW95RbSyuGJH5ZwRwsMJBe/s1600/IMG_1282.JPG

Add the numbers in each column

Two digits in the ones place.
Trade 15 ones for 1 ten and 5 ones.
Move the 1 ten to the tens column.

Two digits in the tens place.
Trade 13 tens for 1 hundred and 3 tens
Move the 1 hundred to the hundreds column


248 + 187 = 435 




I hope this information helped. If you every have more questions about our Everyday Math while you are at home, this is a really helpful site to view!This link will take you to the unit we are currently working on.


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