Learning to Explain Our Math Reasoning
As students master the concept of rounding numbers, we begin to make the work more challenging by having students justify their thinking. We spend several days this week practicing putting our reasons into words.
Mrs. Ferrell provides a sample response for the bottom left question on the Rounding Riddles assignment:
Julia has about 40 coins. Rachel has 37 coins. Could Rachel have more coins than Julia? Explain your thinking.
1. Use a numberline to show your answer. This numberline shows the appropriate numbers and indicates Rachel's amount (37) and how many Julia could have if she rounded to 40. It then shows a number Julia could have that answers the question (35).
2. Answer the question clearly. "Yes, Rachel could have more coins than Julia." This provides the yes/no that the question asks and then restates the question so that the answer is clear.
3. Tell me why your answer is true by using a "because" statement that uses rounding to explain your response. "...because Julia could round 35 to 40." This continues to answer the question by telling why Julia could have more coins. It relates the answer to rounding.
4. If necessary, compare your numbers to show that one is greater than the other. "Rachel's 37 is greater than Julia's 35." Because the question wanted to know if Rachel could have more, we need to finish our explination by comparing our two numbers - 37 and 35 - to show that Rachel does, indeed, have more. Some problems will not need this step. For example, the top 4 question on the Rounding Riddles page only have steps 1-3.
Stella explains her thinking on her Rounding Riddles assignment. She numbers each of our four response pieces. 1. Use a numberline to show your answer. 2. Answer the question clearly. 3. Tell me why your answer is true by using a "because" statement that uses rounding to explain your response. 4. If necessary, compare your numbers to show that one is greater than the other.
After checking their homework, students work with partners to complete similar problems.
Dany and Josh help each other figure out the correct answers to their Rounding Riddles.
Devin helps Chandler, who was absent yesterday, work on his rounding problems.
