Before You Begin This Unit... 
Unit at a Glance 

From 3^{rd} Grade, students bring their ability to add and subtract 2digit and 3digit numbers. They also bring mastery of addition combinations and their related subtraction facts. Look for your students to bring at least 1 addition strategy they can use fluently and efficiently to their work in this unit. Students should also be able to choose and carry out appropriate subtraction strategies. Place value and computational strategies are interwoven throughout this unit in order to help students develop their ability to estimate sums and differences. Some of your students may have working knowledge of the U.S. standard algorithm for addition. This unit will help students connect the algorithm to other strategies that highlight place value and property understandings. In earlier grades, students solve a variety of subtraction problems. In 4^{th} grade, students visualize subtraction situations with a focus on missingpart problems. Visualizing the situation supports students’ understanding and representation of the problem and also helps them consider the relationship between addition and subtraction. 
Suggested Dates: *Investigation 1: 6 lessons (Incl. 1.5A, but combine 1.5 & 1.6) *Investigation 2: 5 lessons (combine 2.3 & 2.4) *Investigation 3: 6 lessons (Incl. 3.6A) *Investigation 4: 8 lessons (Incl. 4.4A)


Standards Addressed in the Unit  
Link to the CCSS Unpacking Document Updated Sept. '15 4.NBT.2 Read and write multidigit whole numbers using baseten numerals, number names, and expanded form. Compare two multidigit numbers based on meanings of the digits in each place, using >, =, and < symbols to record the results of comparisons. 4.NBT.3 Use place value understanding to round multidigit whole numbers to any place. 4.NBT.4 Fluently add and subtract multidigit whole numbers using the standard algorithm. 4.MD.2 Solve problems involving measurement and conversion of measurements from a larger unit to a smaller unit. 