Using concrete models or drawings, strategies based on place value, properties of operations, and explaining the reasoning used, add, within 100, in the following situations:
A two-digit number and a one-digit number
A two-digit number and a multiple of 10
Step 1: Lesson Standards & Learning Goals
The focus of this standard is to develop an understanding and lay a foundation for multi-digit addition using Counting On or Making Ten strategies (NC.1.OA.6) when adding a one-digit number and adding tens using place value strategies when adding a multiple of 10. Students use models, drawings, and place value strategies to add within 100. This work is limited to adding only a two-digit number to either a one-digit number or a multiple of 10. Students should apply their understanding of place value from NC.1.NBT.2 to consider how many tens and ones are in a 2-digit number and write the number in expanded form. Students move beyond basic facts and draw on their understanding of the base-ten system to begin developing strategies for adding one- and two-digit numbers. See the table for strategies.
*The US standard algorithm of carrying or borrowing is neither an expectation nor a focus in First Grade.
How can I show my understanding of adding within 100 by using models and drawings?
What strategies can we use to add two-digit numbers and one-digit numbers?
How does understanding place value help us add numbers within 100?
How do concrete models or drawings help us visualize addition problems?
Why is it important to decompose and compose tens when adding two-digit numbers?
add
addend
decompose
equals
equation
expanded form
ones
place value
strategies
sum
tens
Use manipulatives to demonstrate an understanding of adding a two-digit and one-digit number.
Use expanded form to show the number of tens and ones in a two-digit number.
Add a two-digit number and a multiple of 10 using models and place value strategies.
Adding two-digit numbers means adding ones and ones, tens and tens, and composing a ten as needed.
There are multiple strategies that can be used to add a two-digit number to a one-digit number or multiple of ten.
Our number system is based on multiples of tens.
Step 2: Assessment
NCDPI Math Assessment Released Forms
Grade 1 Math Assessment Practice Prompts
Grade 1 Released Summative Assessments
Step 3: Lesson Instructions
Video Clip
Video Clip
Read Aloud
Tools 4 NC Teachers
Cluster 5 Lessons
Math Expressions - (Barnes and Hearne) - Standards Alignment
Motivation Math
Think Up! Math
Khan Academy - 1st Grade Math
Eureka Math/Engage NY Free Resources
Topic C: Addition and Subtraction of Tens
Topic D: Addition of Tens or Ones to a Two-Digit Number
Topic F: Addition of Tens and Ones to a Two-Digit Number
Topic C: Addition to 100 Using Place Value Understanding
Topic D: Varied Place Value Strategies for Addition to 100
Zearn Math - Online Support Practice for Eureka Math (Requires free account)
North Carolina Collaborative for Mathematics Learning - Grade 1 Instructional Framework
NCDPI Resources
Grade 1 Math Assessment Practice Prompts
