• Amani, Guillermo, Lisette, Yolanda, Ian and Jermaine each have a way to describe what they know about 27. Write a similar explanation that each of the students might use to describe the number 39 (so six different descriptions of "39" total). ALSO, come up with an incorrect description of 39.
• Draw or use images to make at least three different representations of 39 similar to those represented in 9.1 (either with base ten blocks, arrays, unifix cubes or some combination) This is pretty flexible as long as it's accuratethere are many possibilities! ALSO,come up with an incorrect representation of 39 and indicate it as such.

on Amani: Twenty-seven comes after 26 and before 28. F. 1I Guillermo: Twenty-seven is three more than 24 and ige, three smallerthan 30. uild Lisette: Twenty-seven is two groups of ten and seven ones. der- Yolanda: Twenty-seven is 10 more than 17 and 10 ated less than 37 on the hundreds chart. m to Ian: I can count to 27 by threes: 3, 6, 9, 12, 15, 18, 21, blem 24, 27, but counting by fours is 28. Jermaine: Twenty-seven is an odd number be- cause you skip it when you count by twos. of a When making 27 with base-10 materials, some dis- many play 27 with two orange rods and seven white cubes, class others line up 27 loose cubes, 2 bean sticks and 7 beans, or 9 groups of 3 (Figure 9.1). one- plus 7% By observing and listening to children, the teacher learns whether they understand many nu- ong do meral expressions for 27. From student comments and demonstrations, Ms. Chen believes that stu- should dents have developed a flexible understanding inger, or Why do of number and its many representations, so she is ready to introduce the place-value system in a more or 40? out num- 10 + 10+ 7 OOO morizing 00 0. to solve 80008 0808000 10 + 17 e conclu dents un- OOO 5x5+ 2 ers can be k whether OOO 28 - 1 ferent rep- 00000 ooo 000000 rials and a 9 x 3 they know Figure 9.1 Several ways of representing 27