text: # Domain 2.NBT, Number and Operations in Base Ten
  
  ## Cluster 2.NBT.A, Understand place value.
  
  Major Cluster
  
  ### Standard 2.NBT.A.1
  
  Understand that the three digits of a three-digit number represent amounts of hundreds, tens, and ones; e.g., 706 equals 7 hundreds, 0 tens, and 6 ones. Understand the following as special cases:
  
  9 Lessons
  
  53 Activities
  
  ### Standard 2.NBT.A.1.A
  
  100 can be thought of as a bundle of ten tens - called a "hundred."
  
  0 Lessons
  
  1 Activity
  
  ### Standard 2.NBT.A.1.B
  
  The numbers 100, 200, 300, 400, 500, 600, 700, 800, 900 refer to one, two, three, four, five, six, seven, eight, or nine hundreds (and 0 tens and 0 ones).
  
  0 Lessons
  
  0 Activities
  
  ### Standard 2.NBT.A.2
  
  Count within 1000; skip-count by 5s, 10s, and 100s.
  
  14 Lessons
  
  58 Activities
  
  ### Standard 2.NBT.A.3
  
  Read and write numbers to 1000 using base-ten numerals, number names, and expanded form.
  
  11 Lessons
  
  15 Activities
  
  ### Standard 2.NBT.A.4
  
  Compare two three-digit numbers based on meanings of the hundreds, tens, and ones digits, using >, =, and
  
  5 Lessons
  
  12 Activities
  
  ## Cluster 2.NBT.B, Use place value understanding and properties of operations to add and subtract.
  
  Major Cluster
  
  ### Standard 2.NBT.B.5
  
  Fluently add and subtract within 100 using strategies based on place value, properties of operations, and/or the relationship between addition and subtraction.
  
  19 Lessons
  
  146 Activities
  
  ### Standard 2.NBT.B.6
  
  Add up to four two-digit numbers using strategies based on place value and properties of operations.
  
  1 Lesson
  
  2 Activities
  
  ### Standard 2.NBT.B.7
  
  Add and subtract within 1000, using concrete models or drawings and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction; relate the strategy to a written method. Understand that in adding or subtracting three-digit numbers, one adds or subtracts hundreds and hundreds, tens and tens, ones and ones; and sometimes it is necessary to compose or decompose tens or hundreds.
  
  63 Lessons
  
  97 Activities
  
  ### Standard 2.NBT.B.8
  
  Mentally add 10 or 100 to a given number 100-900, and mentally subtract 10 or 100 from a given number 100-900.
  
  17 Lessons
  
  10 Activities
  
  ### Standard 2.NBT.B.9
  
  Explain why addition and subtraction strategies work, using place value and the properties of operations.1
  
  59 Lessons
  
  48 Activities