Addition


 * Common Assessment: Friday September 17**

TEKS: 3.3A 3.3B
 * Uses numbers less than 1000.
 * Uses Base Ten Blocks as models and draws pictures.
 * Models problems involving regrouping.
 * Models problems involving tables.
 * Writes number sentences to represent actions in problems.
 * Uses real world situations.
 * Models and solves with symbols.
 * Connects symbols to models.
 * Identifies operation.
 * Estimates sums and differences before solving.
 * Extracts information from word problems to set up and solve.
 * Solves problems using multiple operations and regrouping.
 * Identifies answers that are too large or too small.


 * Day 1 - 2: Use place value blocks to model addition.**

Using base-ten blocks is a good way to help children visualize what they are doing when adding three-digit numbers with regrouping. To solve an addition problem, regrouping ones, model the addends using base-ten blocks. The example below shows 125 + 137.


 * [[image:http://www.eduplace.com/math/mw/background/2/12/graphics/ts_2_12_wi-1.gif width="183" height="170" caption="Base-ten blocks"]] ||
 * Base-ten blocks ||

Remind children that to add, they should begin with the ones. In this case, group 5 ones and 7 ones to make 12 ones, regroup the ones as 1 ten, 2 ones, add the tens to make 6 tens, and add the hundreds to make 2 hundreds. The answer to the problem is 262. The same process takes place when regrouping 10 tens, except regrouped tens become 1 hundred. The example below shows 153 + 172.


 * [[image:http://www.eduplace.com/math/mw/background/2/12/graphics/ts_2_12_wi-2.gif width="239" height="172" caption="Base-ten blocks"]] ||
 * Base-ten blocks ||

In this case, the ones do not need regrouping. Add to get 5 ones. Then group 5 tens and 7 tens to make 12 tens, and regroup the tens as 1 hundred, 2 tens. Add the hundreds. The answer to the problem is 325.

Give the students plenty of practice using the base ten blocks to model addition.


 * Day 3: Put away the base ten blocks and try the algorithm. This is an EXCELLENT step by step powerpoint for demonstrating that very concept.**

This is an EXCELLENT sheet for practice. It uses a grid to help kids keep all of the numbers in their place. I am thinking it might be fun and beneficial to give the kids centimeter graph paper and have them practice writing problems off the board onto the graph paper and solving from there. That could be an extension to this worksheet. I think kids need to see the importance of having all of their columns lined up properly.
 * Day 4 - 5: Practice, practice, practice!**