standard_description: Add and subtract within 1000, using concrete models or drawings and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction; relate the strategy to a written method. Understand that in adding or subtracting three-digit numbers, one adds or subtracts hundreds and hundreds, tens and tens, ones and ones; and sometimes it is necessary to compose or decompose tens or hundreds.
problem_activity: Fill out the following chart.
| **           Standard form          ** |  **           Unit form          **  | **           Expanded form          ** |
|----------------------------------------|--------------------------------------|----------------------------------------|
|                                        |                                      |            5,000 + 400 + 3             |
|                                        | 8 thousands 6 hundreds 3 tens 2 ones |                                        |
|                 2,061                  |                                      |                                        |


aligns: no