Number Sense and Place Value
Students will develop an understanding of place value through 100s. Students will learn to compare values of up to three digit numbers. Students will develop fluency with adding and subtracting within 20.
Download the complete Grade 2 Math Unit 1 framework to customize for your own planning
Essential Outcomes
Operations and Algebraic Thinking
- NY-2.OA.2a: Fluently add and subtract within 20 using mental strategies. Strategies could include:
- counting on;
- making ten;
- decomposing a number leading to a ten;
- using the relationship between addition and subtraction; and
- creating equivalent but easier or known sums.
- NY-2.OA.4: Use addition to find the total number of objects arranged in rectangular arrays with up to 5 rows and up to 5 columns. Write an equation to express the total as a sum of equal addends.
Number and Operations in Base Ten
- NY-2.NBT.1: Understand that the digits of a three-digit number represent amounts of hundreds, tens, and ones.
- NY-2.NBT. 3: Read and write numbers to 1000 using base-ten numerals, number names, and expanded form.
Other Standards Addressed in this Unit
Operations and Algebraic Thinking
- NY-2.OA.2b: Know from memory all sums within 20 of two one-digit numbers.
- NY-2.OA.3a: Determine whether a group of objects (up to 20) has an odd or even number of members, e.g., by pairing objects or counting them by 2’s.
- NY-2.OA.3b: Write an equation to express an even number as a sum of two equal addends.
Number and Operations in Base Ten
- NY-2.NBT.1a: Understand 100 can be thought of as a bundle of ten tens, called a “hundred.”
- NY-2.NBT.1b: Understand 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).
- NY-2.NBT. 2: Count within 1000; skip-count by 5s, 10s, and 100s.
- NY-2.NBT.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.
- NY-2.NBT.8: Mentally add 10 or 100 to a given number 100-900, and mentally subtract 10 or 100 from a given number 100-900.
Essential Questions and Big Ideas
- How much is a digit worth? How does the position of a number affect its value?
- The value of a digit depends on its place, or position in the number.
- Each place has a value of 10 times the place to its right.
- A digit in the one’s place is worth that number. In the number 524, The one’s place is worth 4 ones, the ten’s place is worth 2 tens or 20 and the hundred’s place is worth 5 hundreds or 500.
- How do mathematical relationships relate to each other?
- Using mental strategies can allow for more fluent addition & subtraction
- Using various methods to represent and solve problems involving addition & subtraction
- Expressing rows and columns of an array using repeated addition equations
- How do we solve word problems?
- Keywords help us determine if we need to add or subtract to solve a word problem.
Download the complete Grade 2 Math Unit 1 framework to customize for your own planning