Unit 8

Understanding Operations Through Place Value

 

Grade 1

Math

Unit Length and Description:

 

3 weeks

 

This unit continues to focus on understanding place value and properties of operations to add and subtract.

 

Standards:

 

CCSS for Mathematical Content

CCSS #

CCSS Text

Operations and Algebraic Thinking

1.OA.1

Use addition and subtraction within 20 to solve word problems involving situations of adding to, taking from, putting together, taking apart, and comparing, with unknowns in all positions, e.g., by using objects, drawings, and equations with a symbol for the unknown number to represent the problem.

1.OA.2

Solve word problems that call for addition of three whole numbers whose sum is less than or equal to 20, e.g., by using objects, drawings, and equations with a symbol for the unknown number to represent the problem.

Numbers and Operations in Base Ten

1.NBT.3

Compare two two-digit numbers based on meanings of the tens and ones digits, recording the results of comparisons with the symbols >, =, and <.

1.NBT.4

Add within 100, including adding a two-digit number and a one-digit number, and adding a two-digit number and a multiple of 10, 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 and explain the reasoning used. Understand that in adding two-digit numbers, one adds tens and tens, ones and ones, and sometimes it is necessary to compose a ten.

1.NBT.5

Given a two-digit number, mentally find 10 more or 10 less than the number, without having to count; explain the reasoning used.

1.NBT.6

Subtract multiples of 10 in the range 10-90 from multiples of 10 in the range 10-90 (positive or zero difference), 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 and explain the reasoning used.

Standards for Mathematical Practice (MP)

MP.1

Make sense and persevere in solving problems.

MP.2

Reason abstractly and quantitatively.

MP.5

Use appropriate tools strategically.

MP.6

Attend to precision.

MP.7

Look for and make use of structure.

Instructional Outcomes

1.OA.1: Use addition and subtraction within 20 to solve word problems involving situations of adding to, taking from, putting together, taking apart, and comparing, with unknowns in all positions, e.g., by using objects, drawings, and equations with a symbol for the unknown number to represent the problem.

  • I can use a symbol (e.g. ?, x) to represent an unknown number in a problem.
  • I can determine the operation to solve word problems with unknowns.
  • I can solve word problems by adding 3 numbers in different ways.

 

1.OA.2: Solve word problems that call for addition of three whole numbers whose sum is less than or equal to 20, e.g., by using objects, drawings, and equations with a symbol for the unknown number to represent the problem.

  • I can add 3 numbers.
  • I can identify parts/addends in a word problem.
  • I can show how to solve word problems.

 

1.NBT.3: Compare two two-digit numbers based on meanings of the tens and ones digits, recording the results of comparisons with the symbols >, =, and <.

  • I can identify the value of each digit in a two-digit number.
  • I can explain what each symbol means (>, <, =).
  • I can compare two 2 digit numbers.
  • I can use >, <, = symbols to compare two 2 digit numbers.

 

1.NBT.4: Add within 100, including adding a two-digit number and a one-digit number, and adding a two-digit number and a multiple of 10, 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 and explain the reasoning used. Understand that in adding two-digit numbers, one adds tens and tens, ones and ones; and sometimes it is necessary to compose a ten.

  • I can show that in adding 2 digit numbers, you add ones to ones and tens to tens.
  • I can recognize when to regroup to compose (make) a ten.
  • I can add a 2 digit number and a 1 digit number within 100.
  • I can add a 2 digit number and 1 digit number with regrouping within 100.
  • I can add a 2 digit number and a multiple of 10 within 100.
  • I can relate the strategy to an equation.
  • I can explain why I used a chosen strategy to solve a written equation.

 

1.NBT.5: Given a two-digit number, mentally find 10 more or 10 less than the number, without having to count; explain the reasoning used.

  • I can mentally add 10 to a given 2-digit number.
  • I can mentally subtract 10 from a given 2-digit number.
  • I can explain how to find 10 more from a given 2-digit number.
  • I can explain how to find 10 less from a given 2-digit number.

 

1.NBT.6: Subtract multiples of 10 in the range 10-90 from multiples of 10 in the range 10-90 (positive or zero difference), 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 and explain the reasoning used.

 

  • I can subtract multiplies of ten up to 90.
  • I can choose a strategy to solve subtraction problems with multiplies of 90.
  • I can relate the strategy to an equation.
  • I can explain why I used the chosen strategy to solve a written equation.

 

 

 

Enduring Understandings:

 

        I can solve different types of addition and subtraction word problems and equations using different strategies.

        I can use place value to compare two numbers.

        I can add two-digit and one-digit numbers with and without composing a group of ten.

       I can explain how I got my answer.

 

 

Essential Questions:

 

        What happens when we join two quantities or take one from another?

        How can we find the total when we join two quantities?

        How can we find what is left when we take one quantity from another?

        How can we find the difference when we compare one quantity to another?

        How can we compare one quantity to another?

        How can I solve different types of addition and subtraction word problems using different strategies?

        How do I explain my answer so that others understand my thinking?