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Clarifications
Clarification 1: Instruction includes the connection to money and the use of manipulatives and models based on place value.Benchmark Instructional Guide
Connecting Benchmarks/Horizontal Alignment
Terms from the K-12 Glossary
- Equation
- Expression
Vertical Alignment
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Purpose and Instructional Strategies
- The purpose of this benchmark is for students to explore addition and subtraction of decimals to the hundredths using manipulatives, visual models, discussions, estimation, and drawing.
- Instruction should focus on strategies based on place value. Through the connection to money, students can build on previous content knowledge about money to add and subtract decimals based on place value. Examples of manipulatives that support understanding when adding and subtracting decimals are base-ten blocks, place-value chips, money (dollars and coins), and place-value mats.
Common Misconceptions or Errors
- A common error that students make is to not add or subtract like place values, especially in an example such as 30.1 + 2.74. Instruction should relate decimals to methods used for whole numbers. When adding whole numbers, ones were added to ones, tens to tens, hundreds to hundreds, and so forth. When adding decimal numbers, like place values are combined, too. Like place values are subtracted, just as with whole numbers.
Strategies to Support Tiered Instruction
- Instruction includes relating decimals to methods used for whole numbers. When adding whole numbers, ones were added to ones, tens to tens, hundreds to hundreds, and so forth. When adding decimal numbers, like place values are combined, too. Like place values are subtracted, just as with whole numbers. The teacher utilizes place value charts so that students can see where to line up values for the computation.
- For example, 20.2 − 9.75 is going to require some regrouping. By placing the problem in a place value chart, students line up the decimal and subtract like place values.
- Instruction includes relating decimal place values. Working with base ten blocks, students build decimals and their equivalents.
- For example, building 0.2 “two-tenths” and 0.20 “ twenty hundredths” with base, ten blocks will help students to realize that the numbers have the same value.
Instructional Tasks
Instructional Task 1 (MTR.7.1)
Tony’s lunchbox weighs 2.5 pounds. He took out his apple which weighs 0.65 pounds. How much does his lunchbox weigh now?
Instructional Items
Instructional Item 1
Match each expression on the left with the equivalent decimal.
*The strategies, tasks and items included in the B1G-M are examples and should not be considered comprehensive.
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Lesson Plans
Original Student Tutorials
Perspectives Video: Expert
Tutorial
STEM Lessons - Model Eliciting Activity
Fourth graders will help Cookies and Treats find cost-effective and eco-friendly packaging for its cookies. Students will organize data and compare prices using decimal notation in order to develop a procedure for choosing packaging for cookies. Students will use multiplication and division of whole numbers to plan for how many packages to order.
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.
Original Student Tutorials Mathematics - Grades K-5
Help these aliens clean up the Sweet Treats Factory by learning to add decimals in this interactive mathematics tutorial.
Learn to subtract decimals to the hundredths place using place-value models and written expressions as you fix the topsy-turvy playground in this interactive tutorial.
STEM Civics Tutorials and Videos - Grades K-12
Learn about sales tax as Malik tries to buy his favorite candy from the store in this short video.
Student Resources
Original Student Tutorials
Learn about sales tax as Malik tries to buy his favorite candy from the store in this short video.
Type: Original Student Tutorial
Learn to subtract decimals to the hundredths place using place-value models and written expressions as you fix the topsy-turvy playground in this interactive tutorial.
Type: Original Student Tutorial
Help these aliens clean up the Sweet Treats Factory by learning to add decimals in this interactive mathematics tutorial.
Type: Original Student Tutorial
Tutorial
This tutorial for student audiences will assist learners with a further understanding of the rules for adding and subtracting with decimals. Students will be able to navigate the teaching portion of the tutorial at their own pace and test their understanding after each step of the lesson with a "Try This" section. The "Try This" section will monitor students answers and self-check by a right answer turning orange and a wrong answer dissolving.
Type: Tutorial
Parent Resources
Tutorial
This tutorial for student audiences will assist learners with a further understanding of the rules for adding and subtracting with decimals. Students will be able to navigate the teaching portion of the tutorial at their own pace and test their understanding after each step of the lesson with a "Try This" section. The "Try This" section will monitor students answers and self-check by a right answer turning orange and a wrong answer dissolving.
Type: Tutorial
