### Examples

*Example:*The sum 41+23 can be found by using a number line and “jumping up” by two tens and then by three ones to “land” at 64.

*Example:* The difference 87-25 can be found by subtracting 20 from 80 to get 60 and then 5 from 7 to get 2. Then add 60 and 2 to obtain 62.

### Clarifications

*Clarification 1:*Instruction focuses on helping a student choose a method they can use reliably.

**Subject Area:**Mathematics (B.E.S.T.)

**Grade:**2

**Strand:**Number Sense and Operations

**Date Adopted or Revised:**08/20

**Status:**State Board Approved

## Related Courses

## Related Access Points

## Related Resources

## Formative Assessments

## Lesson Plans

## Original Student Tutorial

## Tutorials

## STEM Lessons - Model Eliciting Activity

Students will determine which pizza place should be used to cater parties at the Birthday Parties 'R' Us facility given a set of data. They will create a procedure for determining the best pizza place, write an explanation about their procedure, and present their recommendations to the class.

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.

Written at a second grade level, in this MEA the students will use problem solving skills, two-digit addition, and knowledge of greater than and less than to rank order carnival games based on provided criteria.

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.

This MEA asks students to decide which factors are important in choosing the best cookie in a cookie contest. Students will take on the role of cookie critics to provide feedback to a teacher whose grade level is deciding which cookie to use for a fundraiser. They will rank order their choices from the best to worst cookie. Students will provide a detailed written explanation for how they decided to rank factors and their solution. They will show their work while adding up to 4 two-digit numbers to calculate the total number of votes.

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.

This Model-Eliciting Activity (MEA) is designed for a second grade level. Students will be working in small groups to figure out what companies to hire for the art gallery to have a successful charity event. The students will be evaluating criteria such as bands for the event, caterers, and artists. Students will need to add money to stay within a budget. They will write their procedure for making their selections.

## MFAS Formative Assessments

Students add a multiple of 10 to a two-digit number and are asked to relate the strategy used to a written method.

Students are asked to solve two addition problems and are observed for the use of place value strategies.

The student is asked to solve an addition and a subtraction problem in which a decade (i.e., a multiple of ten) must be crossed.

Students use a number line to find to the difference between 17 and 42.

Students are asked to solve three subtraction within 100 problems and are observed for the use of place value strategies.

Students use a number line to add 23 and 19 and to find a segment whose length is the sum of 23 and 19.

Students are asked to solve a two-digit addition problem using a place value strategy and then are asked to explain why this strategy works.

Students are asked to complete addition and subtraction problems that can be done efficiently by using properties of operations.

## Original Student Tutorials Mathematics - Grades K-5

Learn to use place value to solve subtraction problems within 100 in this interactive, basketball-themed tutorial.

## Student Resources

## Original Student Tutorial

Learn to use place value to solve subtraction problems within 100 in this interactive, basketball-themed tutorial.

Type: Original Student Tutorial

## Tutorials

In this tutorial video from Khan Academy, a subtraction problem is solved which contains two numbers each with two-digits. The video demonstrates subtraction with regrouping using the standard algorithm, as well as a method using expanded form.

Type: Tutorial

In this video tutorial from Khan Academy, explore subtracting two-digit numbers by using the standard algorithm. This video does not include regrouping.

Type: Tutorial

In this tutorial video from Khan Academy, explore adding two-digits numbers with base ten blocks and connect this to the standard algorithm. The examples do not include regrouping.

Type: Tutorial

In this video tutorial from Khan Academy, explore the connection between place value and subtraction. This video explains how to solve a subtraction problem with numbers less than one hundred using base ten blocks.

Type: Tutorial

Learn how to add 23 + 30 by thinking about place value.

Type: Tutorial

## Parent Resources

## Tutorials

In this tutorial video from Khan Academy, a subtraction problem is solved which contains two numbers each with two-digits. The video demonstrates subtraction with regrouping using the standard algorithm, as well as a method using expanded form.

Type: Tutorial

In this video tutorial from Khan Academy, explore subtracting two-digit numbers by using the standard algorithm. This video does not include regrouping.

Type: Tutorial

In this tutorial video from Khan Academy, explore adding two-digits numbers with base ten blocks and connect this to the standard algorithm. The examples do not include regrouping.

Type: Tutorial

In this video tutorial from Khan Academy, explore the connection between place value and subtraction. This video explains how to solve a subtraction problem with numbers less than one hundred using base ten blocks.

Type: Tutorial

Learn how to add 23 + 30 by thinking about place value.

Type: Tutorial