2.NBT. Grade 2 - Number and Operations in Base Ten

2.NBT.A. Understand place value.

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:

• Boxes and Cartons of Pencils
• Bundling and Unbundling
• Counting Stamps
• Largest Number Game
• Looking at Numbers Every Which Way
• Making 124
• One, Ten, and One Hundred More and Less
• Regrouping
• Ten \$10s make \$100
• Three composing/decomposing problems

2.NBT.A.1.a. 100 can be thought of as a bundle of ten tens–-called a “hundred.”

• Party Favors

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).

• No tasks yet illustrate this standard.

2.NBT.A.2. Count within 1000; skip-count by 5s, 10s, and 100s.

• Saving Money 2

2.NBT.A.3. Read and write numbers to 1000 using base-ten numerals, number names, and expanded form.

• Looking at Numbers Every Which Way

2.NBT.A.4. Compare two three-digit numbers based on meanings of the hundreds, tens, and ones digits, using $>$, =, and $<$ symbols to record the results of comparisons.

• Comparisons 1
• Comparisons 2
• Digits 2-5-7
• Number Line Comparisons
• Ordering 3-digit numbers
• Using Pictures to Explain Number Comparisons

2.NBT.B. Use place value understanding and properties of operations to add and subtract.

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.

• Ford and Logan Add 45+36
• Jamir's Penny Jar
• Saving Money 1
• Saving Money 2

2.NBT.B.6. Add up to four two-digit numbers using strategies based on place value and properties of operations.

• Toll Bridge Puzzle

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.

• How Many Days Until Summer Vacation?
• Many Ways to do Addition 2
• Peyton and Presley Discuss Addition

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.

• Choral Counting

2.NBT.B.9. Explain why addition and subtraction strategies work, using place value and the properties of operations.Explanations may be supported by drawings or objects.

• Peyton and Presley Discuss Addition