**Unit Overview:**

Andrew wrote this unit for 2nd graders to explore place value and regrouping with addition and subtraction using student-made money manipulatives. This mini project has students "adopting" imaginary creatures and "purchasing" accessories and services for them. This unit takes about three weeks and is composed of daily lessons and activities that foster student engagement through real-world context and opportunities for students to create their own imaginary animals, accessories, and services and to represent these in art. This unit is easily integrated with visual arts through artistic representations of students' creatures, with science through animals and ecosystems, and with ELA through telling and writing stories about their creatures.

**LESSON SEQUENCE:**

**Math Standards COVERED:**

**CCSS.MATH.CONTENT.2.NBT.A.1:**Understand that the three digits of a three-digit number represent amounts of hundreds, tens, and ones; e.g., 706 equals 7 hundreds, 0 tens, and 6 ones.**CCSS.MATH.CONTENT.2.NBT.B.6:**Add up to four two-digit numbers using strategies based on place value and properties of operations.**CCSS.MATH.CONTENT.2.NBT.B.5:**Fluently add and subtract within 100 using strategies based on place value, properties of operations, and/or the relationship between addition and subtraction.

**Assessment:**

**Formative assessments**include checking student math as done through graphic organizers, student math discussions, and math journaling.

**Summative assessment**is done through a pre-assessment and post-assessment of a handful of addition and subtraction problems that require regrouping. Students are encouraged to use money manipulatives and other known strategies to complete this short quiz. Once collected, students receive feedback and each error is categorized as one of the following, and appropriate feedback and/or intervention is given to the student:

- Random answer or unidentified mistake--Addition
- Random answer or unidentified mistake--Subtraction
- Error of inattention (misread operations sign, arithmetic error)
- Defective Algorithm--Addition
- Defective Algorithm--Subtraction