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Math: Developing 3-Digit Addition and Subtraction Strategies

Suggested Time Frame: 20 Instructional Days

        

Focus TEKS

Adding and Subtracting within 1,000 (Two- and Three-Digit Numbers, Sums up to 999)

  • Computation
    • 2.4B add up to four two-digit numbers and subtract two-digit numbers using mental strategies and algorithms based on knowledge of place value and properties of operations
      • 2.2A use concrete and pictorial models to compose and decompose numbers up to 1,200 [999 in this unit] in more than one way as a sum of so many thousands, hundreds, tens, and ones
      • 2.2E locate the position of a given whole number on an open number line
      • 2.2F name the whole number that corresponds to a specific point on a number line
      • 2.4A recall basic facts to add and subtract within 20 with automaticity
      • 2.7B use an understanding of place value to determine the number that is 10 or 100 more or less than a given number up to 1,200 [1,000 in this unit]
      • RRISD 2.7B Skip count forward and backward by ten and one hundred from any given number between 1 and 1,000
      • 2.9C represent whole numbers as distances from any given location on a number line
  • Problem Solving
    • 2.4C solve one-step and multi-step word problems involving addition and subtraction within 1,000 using a variety of strategies based on place value, including algorithms
    • 2.4D generate and solve problem situations for a given mathematical number sentence involving addition and subtraction of whole numbers within 1,000
  • Representing
    • 2.7C represent and solve addition and subtraction word problems where unknowns may be any one of the terms in the problem
Computational Fluency TEKS

Two-Digit Addition and Subtraction

  • 2.4B add up to four two-digit numbers and subtract two-digit numbers using mental strategies and algorithms based on knowledge of place value and properties of operations

Skip Counting by 10 and 100

  • RRISD 2.7B Skip count forward and backward by ten and one hundred from any given number between 10 and 1,000
Spiral Review TEKS

Attributes of 3-D Figures

  • 2.8B classify and sort three-dimensional solids, including spheres, cones, cylinders, rectangular prisms (including cubes as special rectangular prisms), and triangular prisms, based on attributes using formal geometric language
    • 2.8D compose two-dimensional shapes and three-dimensional solids with given properties or attributes

Attributes of 2-D Figures

  • 2.8C classify and sort polygons with 12 or fewer sides according to attributes, including identifying the number of sides and number of vertices
    • 2.8A create two-dimensional shapes based on given attributes, including number of sides and vertices
    • 2.8D compose two-dimensional shapes and three-dimensional solids with given properties or attributes
    • 2.8E decompose two-dimensional shapes such as cutting out a square from a rectangle, dividing a shape in half, or partitioning a rectangle into identical triangles and identify the resulting geometric parts

Measure Area

  • 2.9F use concrete models of square units to find the area of a rectangle by covering it with no gaps or overlaps, counting to find the total number of square units, and describing the measurement using a number and the unit

Measure Time

  • 2.9G read and write time to the nearest one-minute increment using analog and digital clocks and distinguish between a.m. and p.m.