General Information
Subject Area: Mathematics (B.E.S.T.)
Grade: 4
Strand: Number Sense and Operations
Date Adopted or Revised: 08/20
Status: State Board Approved
Benchmark Instructional Guide
Connecting Benchmarks/Horizontal Alignment
Terms from the K-12 Glossary
- Equation
- Expression
Vertical Alignment
Previous Benchmarks
Next Benchmarks
Purpose and Instructional Strategies
The purpose of this benchmark is for students to develop an understanding of place value with tenths and hundredths in addition and subtraction.- This benchmark extends upon students’ thinking about 1 more/less from whole numbers to decimals. Students should continue using place value understanding to reason how adding and subtracting 1 tenth and 1 hundredth changes a number’s value.
- Teachers should use familiar manipulatives to help connect students’ exploration of decimals to whole numbers. These materials include base-ten blocks, tenths, and hundredths charts (modeled after hundred charts students used in primary), and place value mats. During instruction, teachers model correct vocabulary consistently to describe decimals and expect the same from students (e.g., the number 1.09 is read as “ one and 9 hundredths”).
- In this initial exploration of decimal addition and subtraction, the expectation is to develop understanding using manipulatives, visual models, discussions, estimation, and drawings, with the focus being on adding and subtracting 1 tenth and 1 hundredth. This prepares students for the broader exploration of adding and subtracting decimals in MA.4.NSO.2.7.
Common Misconceptions or Errors
- When using base-ten blocks, it is important to first identify the value of each block. Students may have preconceptions about relating units to ones, rods to tens, and flats to hundreds, which can be confusing when their values shift from whole numbers to decimals. Teachers should share the relationship between the blocks (each larger block is ten times larger than the next smaller block) so that students understand they can be used flexibly.
- Students may struggle to understand that one-hundredth is smaller than one-tenth because of one hundred is larger than one ten. During instruction, emphasize that one-hundredth is smaller because it would require 100 hundredths to equal 1 whole and only 10-tenths to equal 1 whole.
Strategies to Support Tiered Instruction
- Instruction includes opportunities to model and represent decimals.
- For example, if a 10 by 10 grid of 100 represents one whole, students shade in 0.4 on the grid using the appropriate language to connect “four-tenths” to the decimal 0.4. Then, students shade in what 0.12 represents. The teacher connects the language “ twelve hundredths” to the decimal 0.12. Students compare the decimals using the visuals. This will help solidify the understanding that tenths are larger than hundredths. Using visuals will also connect the learning of one-tenth more/less and one hundredth more/less.
- Instruction includes building decimals with base ten blocks.
- For example, the teacher asks students to build 0.3 (three-tenths) and 0.4 (four-tenths). Students physically see that 0.3 is one-tenth less than 0.4.
Students physically see that 0.3 is one-tenth less than 0.4.
- During instruction, the teacher shares the relationship between the blocks (each larger block is ten times larger the next smaller block) to demonstrate that they can be used flexibly.
- For example, emphasize that one-hundredth is smaller because it would require 100 hundredths to equal 1 whole and only 10-tenths to equal 1 whole.
Instructional Tasks
Instructional Task 1 (MTR.4.1)
Kathy says that 1 tenth more than 3.9 is 4. Mickey says that 1-tenth more than 3.9 is 3.91. Who is correct? Explain how you know.
Instructional Items
Instructional Item 1
What is one tenth more than 3.8?What is one tenth less than 7?
What is one hundredth more than 15.29?
What is one hundredth less than 7?
*The strategies, tasks and items included in the B1G-M are examples and should not be considered comprehensive.