Add up to four two-digit numbers using strategies based on place value and properties of operations.
Cognitive Complexity Level: 1 – Recall
[divider] [/divider]Students are able to…
- Solves sums with up to four 2-digit addends using a variety of strategies.
- Example: 32 + 16 + 28
- Associative Property: Add 32 + 28 to get 60. Add 16 + 60 which equals 76.
- Place Value:
- Add the tens 30 + 10 + 20 = 60
- Add the ones 2 + 6 + 8 = 16
- Add the two sums 60 + 16 = 76
- Example: 32 + 16 + 28
- Discuss connections among strategies with peers for finding sums with up to 4 2-digit addends creating models (concrete, pictorial, hundreds chart, number lines, equations) to justify reasoning as needed.
[divider] [/divider]Students are able to…because teachers:
- Engage students in variety of problem solving opportunities where students are adding sets of three and four two digit numbers requiring students to justify reasoning through a variety of models (concrete, pictorial, hundreds chart, number lines, equations) to deepen understanding.
- Pose questions to stimulation discussion among students about connections between the strategies emphasizing place value and the properties of addition.
[divider] [/divider]Questions to ask students:
- Ask students if you had to add 16 + 37 + 23 which two addends would you join first and why?
- Sample answer that indicates understanding: (make a ten strategy) “I would join 37 and 23 because I know 7 and 3 make a ten and then I just add the other 5 tens totaling 60.” (near doubles strategy) “I would join 16 and 37 because double 6 is 12 and one more is 13 plus 10 is 23 and 30 more makes 53.”
- Ask students how could you use place value to find the sum of 23 + 64 + 12 + 86?
- Sample answer that indicates understanding: “I could add the tens 20 + 60 + 10 +80 finding a sum of 170 and then the ones 3 + 4 + 2 + 6 totaling 15 making the sum of the four numbers 185.”
[divider] [/divider]Additional Resources:
Additional in depth content knowledge:
http://www.katm.org/flipbooks/2%20FlipBook%20Final%20CCSS%202014.pdf#page=34
Video: Add up to four 2 digit numbers using place value
https://learnzillion.com/lesson_plans/4998-add-up-to-four-2-digit-numbers-using-place-value
[divider] [/divider]Sample Formative Assessment Task:
[divider] [/divider] Resources/Tasks to Support Your Child at Home:
- Learn Zillion Video: Add Up to Four Two-Digit Numbers Using Place Value https://tinyurl.com/yavu2gtp
- What strategy can you use to solve 12 + 14 + 24 ?
- Can you solve it in your head and explain how you broke apart a number to add?