Unit 5: Arithmetic in Base Ten
Lesson 3: Adding and Subtracting Decimals with Few Non-Zero Digits

As with addition, prior to grade 6 students have used various ways to subtract decimals to hundredths. Base-ten diagrams and vertical calculations are likewise used for subtracting decimals. “Unbundling,” which students have previously used to subtract whole numbers, is a key idea here. They recall that a base-ten unit can be expressed as another unit that is 1/10 its size. For example, 1 tenth can be “unbundled” into 10 hundredths or into 100 thousandths. Students use this idea to subtract a larger digit from a smaller digit when both digits are in the same base-ten place, e.g., 0.012 - 0.007. Rather than thinking of subtracting 7 thousandths from 1 hundredth and 2 thousandths, we can view the 1 hundredth as 10 thousandths and subtract 7 thousandths from 12 thousandths.

Unbundling also suggests that we can write a decimal in several equivalent ways. Because 0.4 can be viewed as 4 tenths, 40 hundredths, 400 thousandths, or 4,000 ten-thousandths, it can also be written as 0.40, 0.400, 0.4000, and so on; the additional zeros at the end of the decimal do not change its value. They use this idea to subtract a number with more decimal places from one with fewer decimal places (e.g., 2.5 - 1.028). These calculations depend on making use of the structure of base-ten numbers (MP7).

The second activity is optional; it gives students additional opportunities to practice summing decimals.

Unit 5: Arithmetic in Base Ten
Lesson 4: Adding and Subtracting Decimals with Many Non-Zero Digits

This lesson strengthens students’ ability to add and subtract decimals, enabling them to work toward fluency. Students encounter longer decimals (beyond thousandths), find missing addends, and work with decimals in the context of situations. They decide which operation (addition or subtraction) to perform and which strategy to use when finding sums and differences. They also reinforce the idea that we can express a decimal in different but equivalent ways, and that writing additional zeros after the last non-zero digit in a decimal does not change its value. Students use this understanding to practice subtracting numbers with more decimal places from those with fewer decimal places (e.g., 1.9 - 0.4563).

To solve these problems, students must lean heavily on their understanding of base-ten numbers (MP7). Given problems such as 7 - ? = 3.4567 and 0.404 + ? = 1, they need to think carefully about the meaning of each place value, the meaning of addition and subtraction, and potential paths toward the solution. Along the way, they also begin to see patterns in the calculations, which enables them to become increasingly fluent in finding sums and differences (MP8).

This is an interactive assessment and video designed to teach Adding and Subtracting (Numbers up to 20) - Word Problems to first graders.

This is an interactive assessment and video designed to teach Adding and Subtracting (Numbers up to 20) - Word Problems to first graders.

This short video and interactive assessment activity is designed to teach fourth graders about adding and subtracting terms (numbers to 100).

This tool will be used to help support students understanding of adding and subtracting within 10.  The teacher will work with students in small groups with hands-on manipulatives modeling and practicing adding and subtracting with the students while the rest of the group will be working on their blended activity online.  Reminder, blended learning is very new to kindergarteners, so we must have exposed them to working on technology using the blended learning tool before expecting them to be independent.

Students will learn ways to add using the associative property of addition. Students will view a PowerPoint presentation to introduce associative property of addition.

This short video and interactive assessment activity is designed to teach fourth graders about addition: completing the addition sentence.

You can print out your own flash cards with this addition flash card maker. Allows customization of the card color, content, and number ranges. Other resources include making simple flash cards for multiplication, subtraction, and division.

The purpose of this task is to study some patterns in a small addition table. Each pattern identified persists for a larger table and if more time is available for this activity students should be encouraged to explore these patterns in larger tables.

This is a task from the Illustrative Mathematics website that is one part of a complete illustration of the standard to which it is aligned. Each task has at least one solution and some commentary that addresses important aspects of the task and its potential use.

The lesson is to be used to review the six addition strategies the first grade class has already learned. The strategies are: Add Zero Facts, Count On Facts, Make 10 Facts, Doubles Facts, Add 10 Facts, and Add 9 Facts. It also touches on the equal sign.

Students will be able to comprehend the steps necessary to solve addition problems in 3 different ways (logical, physical, visual). Students will be completing a worksheet activity in groups of 4-5. Students should complete this assignment by the end of class.

What does “civil rights” mean in the Trump era? How and why is the category evolving? This Teach-Out focuses on the civil rights aspects of two current debates–health care and the President’s seven-country travel ban–looking at politics, protest, and law. To understand these better, you will learn about foundational civil rights history dating back to Reconstruction (after the Civil War). You will also hear the perspectives of scholars in law, sociology, and political science, as well as civil rights advocates, who will all discuss how civil rights are defended and contested, often growing and contracting in response to other demands and debates. This Teach-Out ends with a call to action for you: How will you participate as our nation defines our rights?

This unit is to be used with second grade students to teach addition and subtraction strategies, or remediate with students needing extra practice.

This short video and interactive assessment activity is designed to teach fourth graders about one step metric capacity with addition and subtraction - word problems.

This short video and interactive assessment activity is designed to teach third graders about one step addition and subtraction - word problems.

This short video and interactive assessment activity is designed to teach fifth graders about addition in kilograms.

This short video and interactive assessment activity is designed to teach fourth graders about addition of capacities - word problems.

This short video and interactive assessment activity is designed to teach fifth graders about addition of compound unit capacities - word problems.