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• ### Marsha McDonald

Member
July 19, 2020 at 7:13 pm

Concept: Adding two-digit numbers.

13+27

1. Students may use manipulatives to create the 2 separate numerical piles, then add up from one through the next-one at a time.

2. The student may remember that they know how to add two-digit numbers to one digit numbers, but are confused by the two digits. They may attempt the part they know or continue to add individual manipulatives up from the 13.

3. The student may combine the manipulatives to look for a skip counting pattern and begin skip counting and adding any extra pieces at the end, depending on how they lined up the rows by columns. They may also remember the math fact that 13 + 27 is equivalent to 27 + 13 and choose to count up by 13 from 27.

4. At this stage, students may choose base ten blocks as their manipulative recognizing place value and create the 2 numbers separately before adding or regrouping. they may also use a place value chart. If they continue using the previous strategy they might multiply the columns and rows instead of skip counting.

5. I can not remember the term but at this stage students might separate the numbers by there place value (ex., 10+20 and 3+7) to solve. Sum might do (13+7) +20 or (27+3) +10.