Fourth Grade Curriculum Model 1

    Place Value, Rounding, and Algorithms for Addition and Subtraction OVERVIEW In this 25-day Grade 4 module, students extend their work with whole numbers. They begin with large numbers using familiar units (hundreds and thousands) and develop their understanding of millions by building knowledge of the pattern of times ten in the base ten system on the place value chart(4.NBT.1). They recognize that each sequence of three digits is read as hundreds, tens, and ones followed by the naming of the corresponding base thousand unit (thousand, million, billion). 1 The place value chartis fundamental to Topic A. Building upon their previous knowledge of bundling, students learn that 10 hundreds can be composed into 1 thousand, and therefore, 30 hundreds can be composed into 3 thousands because a digit’s value is 10 times what it would be one place to its right (4.NBT.1). Students learn to recognize that in a number such as 7,777, each 7 has a value that is 10 times the value of its neighbor to the immediate right. One thousand can be decomposed into 10 hundreds; therefore 7 thousands can be decomposed into 70 hundreds. Similarly, multiplying by 10 shifts digits one place to the left, and dividing by 10 shifts digits one place to the right. 3,000 = 10 × 300 3,000 ÷ 10 = 300 In Topic B, students use place value as a basis for comparing whole numbers. Although this is not a new concept, it becomes more complex asthe numbers become larger. For example, it becomes clear that 34,156 is 3 thousands greater than 31,156. 34,156 > 31,156 Comparison leads directly into rounding, where their skill with isolating units is applied and extended. Rounding tothe nearest ten and hundred was mastered with three-digit numbers in Grade 3. Now, Grade 4 students moving into Topic C learn to round to any place value (4.NBT.3), initially using the vertical number line though ultimately moving away from the visual model altogether. Topic C also includes word problems