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By Katie Diaz,2015-01-15 01:55
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Mathematical Interventions:

With Manipulatives

Standard/Benchmark:

N.FL.03.08- Use mental strategies to fluently add and subtract two-digit numbers.

Objectives:

value concepts using base ten blocks.

Time: 15 minutes

Procedure:

in standard column addition 1. Set out base ten blocks and write the problem 22 + 39

form on a piece of paper large enough for all students to see. Explain that you will model the first problem and then they will have an opportunity to try them on their own.

2. Make 22 (two longs and 2 cubes) and 39 (three longs and 9 cubes) with the base ten blocks. Lay them down facing the students in a way that matches the number; longs on the left and cubes to the right of the longs.

3. Combine the cubes to see if they can make a long.

4. They can so we will trade 10 cubes for a long. There is now one cube left over so that 1 should be recorded in the cubes column (under the 2 and the 9).

5. One long was created so that should be put in the ten’s column above the 2 and recorded on the piece of paper as 1. Be careful to match the manipulatives with the work!

6. Next, add the longs to see if they can make a flat.

7. They can’t so we count them and record the number, 6, in the longs column.

8. Ask yourself “are there any more numbers to add?” Since there are not the problem is complete. The answer is 61.

9. Allow students to try on their own with the problems 145 + 27 (= 172) and 326 + 217 (= 543).