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Explore subtraction of a one-digit number from a two-digit number.
Examples
Finding 37-6 is the same as asking “What number added to 6 makes 37?”Clarifications
Clarification 1: Instruction focuses on utilizing the number line as a tool for subtraction through “counting on” or “counting back”. The process of counting on highlights subtraction as a missing addend problem.Clarification 2: Instruction includes the use of manipulatives, drawings or equations to decompose tens and regroup ones, when needed.
General Information
Subject Area: Mathematics (B.E.S.T.)
Grade: 1
Strand: Number Sense and Operations
Standard: Develop an understanding of addition and subtraction operations with one- and two-digit numbers.
Date Adopted or Revised: 08/20
Status: State Board Approved
Benchmark Instructional Guide
Connecting Benchmarks/Horizontal Alignment
Terms from the K-12 Glossary
- NA
Vertical Alignment
Previous Benchmarks
Next Benchmarks
Purpose and Instructional Strategies
The purpose of this benchmark is to deepen students’ understanding of place value while students explore subtraction. There is no expectation of procedural reliability until grade 2 within this given range. In Kindergarten, students explored subtracting within 20 and subtracting within 10 with procedural reliability. In Kindergarten students counted forward to 100 by 1s and 10s and backward by 1s within 20.- Instruction focuses on choosing a strategy that makes sense to the student based on the given numbers, while guiding students to appropriate and more efficient strategies (MTR.2.1, MTR.5.1).
- Strategies include counting back, skip-counting, decomposing and composing, subtracting ones and tens, and decomposing tens for more ones when needed.
- The expectation for instruction of this benchmark does not include the use of an algorithm, but students should not be prevented from using an algorithm if they can use it reliably. However, the intent of this benchmark is for all students to deepen their understanding of place value while exploring subtraction. There is no expectation of procedural reliability until grade 2 within the range of this benchmark.
Common Misconceptions or Errors
- Students may reverse the minuend and subtrahend in the ones, from the assumption the minuend must be larger than the subtrahend (i.e., for 12 − 5, finding 15 − 2). In these cases is it important for students to use concrete manipulates such as base ten blocks as they must exchange a tens rod for ten ones so that they may physically take away from the ones place.
- Students may fail to subtract a ten from the difference when decomposing a ten to gain enough ones to subtract the ones. In these cases, it can be helpful for students to use base ten blocks to manipulate the exchange of a single tens rod for ten one units to subtract.
Strategies to Support Tiered Instruction
- Instruction includes providing context to the subtraction problem to ensure that students understands that the minuend is the amount that the student will take from. At this stage of the learning progress the minuend is greater than the subtrahend. Teacher should not refer the minuend as always being greater than the subtrahend as this will lead to a later misconception.
- Instruction includes the use of base ten blocks, place value chart, hundreds chart, and/or number line. Teacher provides a subtraction problem and students may solve using manipulatives like the ones listed. Teacher may need to assist in regrouping of tens and ones to subtract. Students may need to use the number line or hundreds chart to count back to solve.
- For example, the teacher provides students with a problem like 33 − 6. Students may use base ten blocks and take away the 6. Teacher may need to remind students that regrouping of a ten may be needed. Teacher asks students what they need to do to subtract 6.
- For example, teacher provides students with a problem like 33 − 6. Student may use a number line and count back 6 to find the difference. Teacher asks the student about how the digits change when counting back and demonstrates how the numbers change when counting by using the hundreds chart as a tool.
Instructional Tasks
Instructional Task 1 (MTR.4.1)
Edward has 88 cents in his jacket pocket. There was a small tear and a nickel slipped out.- Part A. How many cents does Edward have now? Use a number line to show your work. Write a subtraction equation to represent this problem.
- Part B. Compare your number line and equation with a partner, did you both start at the same place on your number line? Did you both get the same answer?
Instructional Items
Instructional Item 1
- To find the difference of 74 − 6, Tanya first subtracted 4 to get 70. What could her next step be? What is the difference? Use Tanya’s strategy to find 35 − 6.
Instructional Item 2
Use a number line to model how you would find the difference of 64 − 9.
Instructional Item 3
To find 32 − 8, a student used base ten blocks. After removing 2 ones, the student is not sure what else to do. What might the next step be? Use this strategy to find 32 − 8.
*The strategies, tasks and items included in the B1G-M are examples and should not be considered comprehensive.
Related Courses
This benchmark is part of these courses.
5012030: Grade One Mathematics (Specifically in versions: 2014 - 2015, 2015 - 2022, 2022 - 2024, 2024 and beyond (current))
7712020: Access Mathematics Grade 1 (Specifically in versions: 2014 - 2015, 2015 - 2018, 2018 - 2022, 2022 and beyond (current))
5012005: Foundational Skills in Mathematics K-2 (Specifically in versions: 2019 - 2022, 2022 - 2024, 2024 and beyond (current))
Related Access Points
Alternate version of this benchmark for students with significant cognitive disabilities.
MA.1.NSO.2.AP.5: Explore subtraction of a one-digit number from a two-digit number from 11 to 19.
Related Resources
Vetted resources educators can use to teach the concepts and skills in this benchmark.
Lesson Plans
Perspectives Video: Expert
Tutorials
Student Resources
Vetted resources students can use to learn the concepts and skills in this benchmark.
Tutorial
Understanding place value while subtracting ones:
Learn how to subtract 4 from 46 by thinking about place value.
Type: Tutorial
Parent Resources
Vetted resources caregivers can use to help students learn the concepts and skills in this benchmark.
Tutorial
Understanding place value while subtracting ones:
Learn how to subtract 4 from 46 by thinking about place value.
Type: Tutorial
