Teacher presentation materials. Unit: 2.2 Adding and Subtracting within 100 (Grade 2). 2.2 Adding and Subtracting within 100 Unit Goals Students add and subtract within 100 using strategies based on place value, properties of operations, and the relationship between addition and subtraction. They then use what they know to solve story problems. Section A Goals Add and subtract within 100 using strategies based on place value and the relationship between addition and subtraction. Problems in this section are limited to the problems like 65 – 23, where decomposing a ten is not required. Section B Goals Subtract within 100 using strategies based on place value, including decomposin