Table of Contents

Unit 3: Reasoning and Explaining (MP2 and MP3)

Student Solutions

Below are several student responses to the Flower Arrangements task. For ease of reading, a photo and a typed transcript below the photo are included.

After reviewing your list of constraints, identify which are addressed and which are missing. In each case, what questions would you ask the students to help them revise their written arguments?


“I did addition and then I just guessed a random number for tulips; then I remembered that there is more tulips than roses and roses than lilies, so I went down by 2 number and then added 5 + 3 + 1 and it equaled 9. I was thinking of an even number being a problem but then in the direction it said, ‘She does odd numbers’.”


“I figured it out with the clues. Tim’s grandmother always uses an odd number, and there are more tulips than roses and more roses than lilies. She is using 9 flowers today which is an odd number [II II II II I]. 5 is odd [II II I], because there is one left out. 3 is odd, because there is one left out [II I]; and, 1 is odd, because it has no partner.”


“I figured this out by looking at the odd numbers and seeing which one I could use without going too high. So I chose numbers 5, 3, 1, and they add up to 9. You can’t get to an odd number by going by 2.”