Standard 2: Develop an understanding of addition and subtraction operations with one- and two-digit numbers.

Students solve a word problem by subtracting a multiple of 10 from a multiple of 10.

Type: Formative Assessment

Students solve two problems, each in more than one way, and are encouraged to use more sophisticated strategies.

Type: Formative Assessment

Students are encouraged to use more sophisticated strategies to solve a part-part-whole problem.

Type: Formative Assessment

Students solve addition and subtraction problems by making tens, using a known fact, and by using a subtraction fact.

Type: Formative Assessment

Students subtract 10 from 50 and explain their strategies.

Type: Formative Assessment

Students mentally subtract ten from a two-digit number.

Type: Formative Assessment

Students are asked to solve a word problem by mentally subtracting 10.

Type: Formative Assessment

Students subtract a multiple of 10 from a multiple of 10.

Type: Formative Assessment

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

Type: Formative Assessment

Students solve an addition and a subtraction problem in more than one way.

Type: Formative Assessment

Students mentally add ten to a given number of shells.

Type: Formative Assessment

Students work with cubes or color tiles to understand and justify the Commutative Property of addition.

Type: Formative Assessment

Students solve a problem by mentally adding ten to a two-digit number.

Type: Formative Assessment

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

Type: Formative Assessment

Students will listen to the book, Quack and Count by Keith Baker, and use the information in the book along with manipulatives to create addition equations. Students will then relate the addition equation to a subtraction equation. Specifically, students will be working on creating the addition and related subtraction facts with the number combinations for 7.

Type: Lesson Plan

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. 

Type: Lesson Plan

This project is to be used at the end of the school year once all the addition and subtraction strategies have been taught. This is a review of the strategies and is an excellent way for students to show what they know about their understanding of addition and subtraction strategies.

Type: Lesson Plan

This lesson will teach students a strategy to subtract one-digit numbers from teen numbers by thinking addition and making-a-ten using double ten frames and two-color counters. This lesson supports previous work with restating subtraction problems as missing addend problems.

Type: Lesson Plan

Teams of students will use math to solve an open-ended, real-world problem to help their parent or caregiver choose the best babysitter. Students will apply mathematical skills of place value (two-digit number tens and ones) and counting to perform math calculations while analyzing data sets. This MEA will facilitate students demonstrating higher level critical thinking and problem solving during class discussions and in writing.

Model Eliciting Activities, MEAs, are open-ended, interdisciplinary problem-solving activities that are meant to reveal students’ thinking about the concepts embedded in realistic situations. Click here to learn more about MEAs and how they can transform your classroom.

Type: Lesson Plan

In this lesson, students will use the "make-a-ten" strategy to add two whole numbers within 20. Students will utilize a ten frame and 2-color counters to complete this activity.

Type: Lesson Plan

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.

Type: Lesson Plan

In this lesson, students will use manipulatives to decompose two-digit numbers into tens and ones. The students will then find ten more or ten less by adding or subtracting “just ten”. This will also be demonstrated on a hundreds chart.

Type: Lesson Plan

In this lesson, students will use the hundreds chart to discover a strategy to subtract 9 from different numbers. Students will learn and practice the compensation strategy of subtracting 10 and then adding 1 back to get the final difference. Students will also learn and practice visualizing to “mentally see” the hundreds chart and use it as an efficient mental math strategy to subtract 9 from any given two-digit number.

Type: Lesson Plan

Students will learn to identify the number that is ten more or ten less than any given two-digit number by playing a game.

Type: Lesson Plan

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.

Type: Lesson Plan

In this lesson, students will play a game involving adding ten to, and subtracting ten from, multiples of ten. In the follow-up lesson, Adding and Subtracting Ten Challenge (Resource ID#: 45832), students will use the foundation gained in this lesson to find ten more and ten less than any given two-digit number.

Type: Lesson Plan

In this lesson, students will find ten more and ten less than any given two-digit number on a hundreds chart. They will learn about and identify the patterns that evolve when this task is performed. Then students will mentally find and write ten more and ten less independently.

Type: Lesson Plan

This lesson outlines a game that is a fun and engaging to practice the make a ten strategy, within 20.

Type: Lesson Plan

In this lesson, the students will be adding and subtracting 10 to/from a given two-digit number. The students will recognize patterns that occur and use these patterns to mentally identify the number that is 10 more or less than a given number.

Type: Lesson Plan

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.

Type: Lesson Plan

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.

Type: Lesson Plan

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.

Type: Lesson Plan

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

Type: Lesson Plan

In this lesson, students will use counting strategies to help them line up in numerical order using numbers from 1 to 120. They will also use hundred charts to help find missing numbers in a number sequence.

Type: Lesson Plan

Students will learn strategies to identify ten more and ten less than a given two-digit number. The lesson begins concretely using base-ten blocks, then to the representational using a hundred chart. Ultimately, the lesson moves to the abstract level where students mentally identify ten more and ten less than a given two-digit number.

Type: Lesson Plan

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.

Type: Lesson Plan

This lesson teaches students to use the strategy doubling numbers and doubles plus or minus one in order to use mental math to add one-digit numbers. The students are engaged in learning through the read-aloud of "Double the Ducks" by Stephen Murphy and then get to work with a partner to draw doubles and write equations that relate to their drawings. Students individually work on solving word problems using these strategies and manipulatives as necessary to solve.

Type: Lesson Plan

In this lesson, you will find activities that you can use to enable student learning and application of mental math addition (using the make a ten strategy) without using rote memorization.

Type: Lesson Plan

Explore strategies to add or subtract ten from a two-digit number in this interactive tutorial.

Type: Original Student Tutorial

Change the order of the numbers in an addition sentence and use the counting on strategy to become quicker at your math facts in this interactive tutorial.

Type: Original Student Tutorial

How are fluency and automaticity defined? Dr. Lawrence Gray explains fluency and automaticity in the B.E.S.T. mathematics benchmarks in this Expert Perspectives video.

Type: Perspectives Video: Expert

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. maththematics benchmarks in this Expert Perspectives video.

Type: Perspectives Video: Expert

What does automaticity look like? What is the role of automaticity in mathematics? Dr. Lawrence Gray explores what it means for students to have automaticity with basic mathematics facts in this Expert Perspectives video.

Type: Perspectives Video: Expert

Unlock an effective teaching strategy for connecting geometry and numbers in order to build number sense in this Teacher Perspectives video for educators.

Type: Perspectives Video: Teaching Idea

In all versions, students must engage basic addition and subtraction facts. In the memory version, after a student has turned over one card, in order to know whether there is a match using cards they've seen, they need to to solve equations of the form ?+b=c, b+?=c, ?-b=c, and b-?=c.

Type: Problem-Solving Task

Learn how to subtract 14 - 6 by first thinking about subtracting 2 and 4.

Type: Tutorial

Learn how to add 8 + 7 by making a group of ten.

Type: Tutorial

In this tutorial, you will learn how to add 7 + 6 using a number line and objects to count.

Type: Tutorial

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.

Type: Tutorial

Learn how to subtract 4 from 46 by thinking about place value.

Type: Tutorial