General Information
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 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.