Standard #: MA.1.NSO.2.4


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Explore the addition of a two-digit number and a one-digit number with sums to 100.


Clarifications


Clarification 1: Instruction focuses on combining ones and tens and composing new tens from ones, when needed.

Clarification 2: Instruction includes the use of manipulatives, number lines, drawings or models.



General Information

Subject Area: Mathematics (B.E.S.T.)
Grade: 1
Strand: Number Sense and Operations
Status: State Board Approved

Benchmark Instructional Guide

Connecting Benchmarks/Horizontal Alignment

 

Terms from the K-12 Glossary

  • Expressions 
  • Equations

 

Vertical Alignment

Previous Benchmarks

 

Next Benchmarks

 

Purpose and Instructional Strategies

The purpose of this benchmark is for students to critically think about choosing a strategy that makes sense based on their given numbers. In Kindergarten, instruction focused on adding single digit whole numbers up to 10. Students recited number names to 100 and counted forward and backward within 20. 
  • Instruction includes guiding students to appropriate and more efficient strategies. Strategies may include, but are not limited to, counting on, skip-counting, decomposing and composing, combining ones and tens, and composing new tens from ones when needed (MTR.2.1, MTR.5.1). 
  • The expectation for instruction does not include the use of an algorithm, but students should not be prevented from using an algorithm if they can use it reliably. However, the intent of this benchmark is for all students to deepen their understanding of place value while exploring addition. There is no expectation of procedural reliability until grade 2 within the range of this benchmark (MTR.5.1).

 

Common Misconceptions or Errors

  • Students may inaccurately compose new tens when they have more than 9 ones. In these cases it is important for students to use concrete manipulatives such as base ten blocks as they exchange tens ones for a single ten rod in order to visually see the ones units making a new ten.

 

Strategies to Support Tiered Instruction

  • Instruction includes the use of base ten blocks, place value chart, and number lines. Teacher provides an addition express with 2-digit and 1-digit addends and allows students to solve the addition problem with a manipulative and a representation. 
    • For example, teacher provides students with a problem like 28 + 4. Students may represent the addition problem using the base ten blocks on a place value chart. If they do not regroup, ask them if they can compose a group of ten ones. 

base ten blocks, place value chart, and number lines

    • For example, teacher provides a problem like 64 + 7. Students may represent the addition problem on a number line. Using this representation shows that the student is counting on. Ask them if they notice how the digits change from 69 to 70 as they counted on the number line. 

  • Instruction includes the use of base ten blocks, place value chart and hundreds chart. Teacher provides a 2-digit number and has students build the number with the base ten blocks on the place value chart. Then, the teacher tells them that they are adding a 1-digit number to the number of blocks they already have. Teacher asks, “What number do you have now?” Exchange the 10 ones for 1 ten rod. Repeat with several problems with and without regrouping. 
    • For example, teacher provides students with the problem 36 + 5 and has students build 36 with base ten blocks and place on the place value chart. Then, students add 5 more ones to the chart. The teacher asks students, “What is your sum? Do you need to regroup?” Repeat with and without regrouping and ask if they need to regroup each time.

ample, teacher provides students with the problem 36 + 5 and has students build 36 with base ten blocks and place on the place value chart

 

Instructional Tasks

Instructional Task 1 (MTR.4.1

Pair students in groups of two and provide each group with the table below, two dice and base ten blocks (1 hundred mat, 12 tens rods per student, 20 ones per student). 

table

  • Part A. Students take turns rolling two dice to determine their starting number using one die to represent the tens place and one die to represent the ones place. Both students build their starting number with base ten blocks. The student who has the smallest starting number starts the game. 
  • Part B. The first student rolls a single die to add that amount to their starting number. The student writes the addition sentence they would use to get their new number. The student must decide if they have enough ones to exchange for a tens rod. If the student has 10 or more ones then they ask their partner to exchange their 10 ones for a tens rod. 
  • Part C. The student writes their new number down. Then they write that new number as their starting number on the next row but wait for their turn before completing the row. 
  • Part D. The second student rolls a single die and completes one row before the first student goes again.

 

Instructional Items

Instructional Item 1 

To find 68 + 7, Jamal added 5 to 70 and got 75. Explain Jamal’s strategy. Is Jamal correct? Write another expression where his strategy can be used. 

Instructional Item 2 

When adding 56 and 6 using base 10 blocks, Jasmine realized she now has 5 tens and 12 ones. What might be Jasmine’s next step to find the sum of 56 + 6? 

adding 56 and 6 using base 10 blocks

 

*The strategies, tasks and items included in the B1G-M are examples and should not be considered comprehensive.




Related Courses

Course Number1111 Course Title222
5012030: Grade One Mathematics (Specifically in versions: 2014 - 2015, 2015 - 2022, 2022 - 2024, 2024 and beyond (current))
7712020: Access Mathematics Grade 1 (Specifically in versions: 2014 - 2015, 2015 - 2018, 2018 - 2022, 2022 and beyond (current))
5012005: Foundational Skills in Mathematics K-2 (Specifically in versions: 2019 - 2022, 2022 - 2024, 2024 and beyond (current))


Related Access Points

Access Point Number Access Point Title
MA.1.NSO.2.AP.4 Explore the addition of a two-digit number from 11 to 19 and a one-digit number.


Related Resources

Formative Assessments

Name Description
Muffins

Students add a one-digit number to a two-digit number that requires composing a ten.

Adding Within 100

Students add a one-digit number to a two-digit number and are asked to relate the strategy used to a written method.

Lesson Plans

Name Description
Counting Coral Reef Babies

Students will listen to the book Over in the Ocean in a Coral Reef, by Marianne Berkes. They will participate in an inquiry to figure out how many baby animals are in the book. They will show the number of animals in the book in groups of ten and some left over. This lesson is a beginning place value and addition lesson for first grade. 

Over a Hundred Hungry Ants: Counting to 120

In this fun lesson, students will use ant manipulatives, hundred charts and the book "One Hundred Hungry Ants" to show how to count to 100 and 120 starting on any given number.

Adding 9 the

In this lesson, students will use the hundreds chart to discover a strategy to add 9 to different numbers. Students will then learn to visualize the hundreds chart as an efficient mental math strategy to add 9 to any given two-digit number.

Race to 99

Students will play a game with tens and ones in a place value chart to ultimately reach 99. Students will physically manipulate unifix cubes or place value blocks to add on one-digit numbers to two-digit numbers, composing new tens when necessary. Students will write equations to represent the addition situations that have been generated.

Make a Ten To Make Adding Easy!

In this lesson students will add two-digit numbers to one-digit numbers by using the "make a ten" strategy. Students will decompose a two-digit number using expanded form, make a ten, and then add. This lesson is an important lesson for students to be able to add greater numbers as they get into higher grade levels.

Ten-Hut!

This lesson allows students to gain insight into how to use place value when adding a two-digit number and a one-digit number. The focus is on students using their bodies, as well as math manipulatives, to solve addition problems within 100 that do not require regrouping.

Coin Combinations: How else can you pay for that?

In this lesson, students will learn that there can be multiple ways (multiple coin combinations) to reach a given money amount. Using money manipulatives, students will work cooperatively and independently to practice finding different coin combinations for a given money amount. Students will also become comfortable knowing that there are multiple ways to reach a correct answer.

Perspectives Video: Experts

Name Description
Addition Within 100 Strategies

Explore ways students may solve addition problems within 100 and how to support their understanding in this video.

FCR-STEM’s Count Us In! initiative is designed to support out-of-school providers and parents in fostering math success and enjoyment among K-5 children.

B.E.S.T. Journey

What roles do exploration, procedural reliability, automaticity, and procedural fluency play in a student's journey through the B.E.S.T. benchmarks? Dr. Lawrence Gray explains the path through the B.E.S.T. mathematics benchmarks in this Expert Perspectives video.

Tutorial

Name Description
Adding by getting to group of 10 first

In this tutorial video from Khan Academy, explore how making a ten can help to make thinking about addition easier. This video includes an example of adding a one-digit number to a two-digit number by decomposing the one-digit number.

Worksheets

Name Description
Open Number Line

Open Number Line

Hundred Chart

Hundred Chart

Double Ten Frame

Double Ten Frame

Tens and Ones Place Value Chart

Tens and Ones Place Value Chart

Student Resources

Tutorial

Name Description
Adding by getting to group of 10 first:

In this tutorial video from Khan Academy, explore how making a ten can help to make thinking about addition easier. This video includes an example of adding a one-digit number to a two-digit number by decomposing the one-digit number.

Worksheets

Name Description
Open Number Line:

Open Number Line

Hundred Chart:

Hundred Chart



Parent Resources

Perspectives Video: Expert

Name Description
Addition Within 100 Strategies:

Explore ways students may solve addition problems within 100 and how to support their understanding in this video.

FCR-STEM’s Count Us In! initiative is designed to support out-of-school providers and parents in fostering math success and enjoyment among K-5 children.

Tutorial

Name Description
Adding by getting to group of 10 first:

In this tutorial video from Khan Academy, explore how making a ten can help to make thinking about addition easier. This video includes an example of adding a one-digit number to a two-digit number by decomposing the one-digit number.

Worksheet

Name Description
Open Number Line:

Open Number Line



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