Family Support Materials. Unit: 2.7 Adding and Subtracting within 1,000 (Grade 2). 2.7 Adding and Subtracting within 1,000 Unit Goals Students use place value understanding, the relationship between addition and subtraction, and properties of operations to add and subtract within 1,000. Section A Goals Add and subtract numbers within 1,000 without composition or decomposition, and use strategies based on the relationship between addition and subtraction and the properties of operations. Section B Goals Add numbers within 1,000 using strategies based on place value understanding, including composing a ten or hundred. Section C Goals Subtract numbers within 1,000 using strateg