Developing Fact Fluency

Addition & Subtraction Through 20

About the Math
Preferred Resources
Additional Resources
Independent Work
Assessment

Full Standard

Fluently add and subtract within 20 using mental strategies. By end of Grade 2, know from memory all sums of two one-digit numbers.

Learning Targets (I can)

Recall facts that add and subtract within 20.
Use mental strategies to recall a fact when a fact can't be recalled quickly.

About the Math

Recall facts that add and subtract within 20.

This standard is a continuation of basic fact instruction started in first grade. Instruction in basic facts should focus on making sense, using strategies for remembering facts, and seeing relationships. Students need to understand the relationship of addition and subtraction as well as the commutative property. When students see the relationships such that 3 + 5 = 8 and that 5 + 3 = 8, they lessen the number of facts that need to be learned.

Use mental strategies to recall a fact when a fact can't be recalled quickly.

Recalling basic facts takes time. Instant recall of the basic facts varies from child to child. Strategies, or ways of thinking about facts, are useful for recalling facts. They are more efficient than consistently drawing or using physical models. They also hope students see patterns.

The sequence of strategy instruction in grade 2 is

Revisit strategies from grade 1 (quarter 1)
Using Ten (facts that make a ten and have some more, eg. 9 + 5, 8 + 5, 14 - 9, etc)
Using Doubles (facts that use the doubles strategy, eg 5 + 4, 9 - 5)
Work with all facts (mixed review, connection and/or extension of strategies)

The use of timed tests is discouraged as a method of learning. Timed tests are only appropriate after students have indicated that they know the facts. Use of timed-assessments should not occur more than once every three to four weeks. Basic facts allow students to be accurate and efficient in computation and mental math.

Essential vocabulary for this standard includes: Doubles, Make ten, Near doubles, sum, difference, added, count-on, count-back, think addition, strategy, part, total, subtract, add, pattern, addition, and subtraction.

Progression of Standard within Grade 2

This progression informs how to develop the standard within the grade level. This progression is provided by HCPSS Elementary Mathematics.

Quarter 1

Quarter 2

Quarter 3

Quarter 4

Recall facts that add and subtract within 20.
Use mental strategies to recall a fact when a fact can't be recalled quickly.

Review grade 1 facts: +/- 0, 1, 2; make ten; +/- 10; doubles

Recall facts that add and subtract within 20.
Use mental strategies to recall a fact when a fact can't be recalled quickly.

Using Ten (Make Ten and Some More)

(i.e. 8 + 5 = 13, 9 + 6 = 15)

Recall facts that add and subtract within 20.
Use mental strategies to recall a fact when a fact can't be recalled quickly.

Using doubles (Near Doubles)

(i.e. 5 + 6 = 11, 8 + 7 = 15)

Recall facts that add and subtract within 20.
Use mental strategies to recall a fact when a fact can't be recalled quickly.

All facts

Progression of this Standard Across Grades

This progression is informed by the Achieve the Core Coherence Map. Information is not the complete standard.

Grade 1	Grade
Fluently add and subtract within 10 (1.OA.6)	This concept is not taught after grade 2. Students are expected to apply the standard proficiently.

Back to Top

Preferred Tasks

These links provide ideas for lessons connected to this standard. They may support small group instruction or whole group collaborative investigations. They are intended to serve as a starting point for planning.

Mixed Facts (all strategies taught):

3D Bullseye

Disappearing Train +++
Box of Sweets +++
Number Puzzles +++
Hitting The Target Number (Illustrative Math)

All Print Resources from Mastering the Basic Facts Addition and Subtraction: +-facts.zip

Lesson Seeds (Prompts for Rigor)

Rigorous mathematics instruction balances the teaching and learning of conceptual understanding, procedural understanding, and the application of mathematics standards. Below are prompts for applying rigor in your classroom. They may support small group instruction or whole group collaborative investigations. They are intended to serve as a starting point for planning. See the Increasing Rigor page for more information.

(making 20) Beth had a pack of 20 pencils. The pencils were two different colors. Show all the combinations of pencils she could have that equal 20. Draw pictures and write equations to support your answer.
If you don’t know 9 + 3, how can knowing 10 + 2 help you?
If you don’t know 9 + 8, is there a doubles fact that can help you? How?
(use of strategies) If you don’t know the sum of 8 + 5 (or any other fact), what are some good strategies you can use to help you figure out the answer? (finger counting isn’t appropriate, looking for mental math ideas) Have students think, pair, share ideas. Write all ideas on board for class to see.
(making 10) Meghan wants to have 10 donuts in each box. How many more donuts does she need to put in each of the following boxes? A box with 9 donuts? A box with 8 donuts? A box with 3 donuts?
(doubling) Sherry already has 4 erasers. Now her goal is to collect 20 in all. She got 4 more on Monday and 8 on Tuesday. How many does she have in all? How many more does she need to make her goal?
(halving) Connie and Cheryl are twins. Connie’s hair is twice the length of Cheryl’s hair. Connie has decided that she wants to cut her hair to be the same length as her sister’s. Connie’s hairdresser measured her hair and it is 16 inches long. How long will the twins’ hair be?

+++ Indicates recently created HCPSS instructional tasks. These tasks are provided in Google slides. When selected, a copy of the file is added to your drive for classroom use.

Back to Top

Print Resources

These publications have been provided for each school. They are typically stored in team closets or the media center. Check with your team leader if you cannot find them.

Book Title	Grade	Pages
Teaching Student-Centered Mathematics	K-3	100 (One/Two-More- Than Dice, Activity 4.1) 100 (One/Two-More- Than Match, Activity 4.2) 100 (Lotto for +1/+2, Activity 4.3) 100 (What's Alike? Zero Facts, Activity 4.4) 101 (Double Images, Activity 4.5) 101 (Calculator Doubles, Activity 4.6) 102 (Double Dice Plus One, Activity 4.7) 103 (Make 10 on the Ten-Frame, Activity 4.5) 104 (If You Didn't Know, Activity 4.9) 106 (A Plus-Five Machine, Activity 4.10) 106 (Say the Ten Fact, Activity 4.11) 109 (Build Up Through the Ten-Frame, Activity 4.12) 109 (Back Down Through the Ten-Frame, Activity 4.13) 110 (Missing-Number Cards, Activity 4.14) 111 (Find a Plus Fact to Help, Activity 4.16)
Mastering The Basic Facts in Addition and Subtraction	K-2	Quarter 1: Review grade 1 facts: +/- 0, 1, 2; make ten; +/- 10; doubles Chapters 2, 3, 4, 5, and 6 Quarter 2: Make ten and some more (i.e. 8 + 5 = 13, 9 + 6 = 15) Chapter 7 Quarter 3: Near doubles (i.e. 5 + 6 = 11, 8 + 7 = 15) Chapter 8 Quarter 4: All facts
Nimble With Numbers	1-2	33-100
Groundworks: Reasoning about Number	2	64-72
Math Intervention: Building Number Power	PK-2	125 (Adding Doubles and Near Doubles) 131-136 (Fact Families)
Roads to Reasoning	2	40 (Double Desser)
Math In Practice Teaching Second-Grade Math	2	Module 2

Children's Literature Connections

Children’s Literature provides an opportunity to put mathematics in context. These titles connect well with this standard.


Two of Everything by Lily Toy Tong	Mrs. Wishy-Washy by Joy Cowley	Domino Addition by Lynette Long	Math-erpieces: The Art of Problem Solving by Greg Tang

Ten Flashing Fireflies by Philemon Sturges	Ready, Set, HOP! by Stuart Murphy	Mouse Count by Ellen Stoll Walsh

Back to Top

Student-Facing Centers

These links provide online and print resources to engage students during independent or center time. These resources could be used as lesson seeds.

Review of 1st Grade Strategies Taught:

Interactive Ten Frame (NCTM Illuminations student-facing resource, pictured)

Make 10 and Some More (+/-):

10 and Some More (HCPSS-adapated resource)
Smart Sums (print resource)

Near Doubles (+/-):

Cover All (Doubles Minus One) (HCPSS-adapated resource)
Cover All (Doubles Plus Two) (HCPSS-adapated resource)
Near Doubles Match Up (HCPSS-adapted resource)
Near Doubles Add and Subtract Match (HCPSS-adapted resource)
Up Down Near Doubles (HCPSS-adapted resource)
Near Doubles Match (print resource)

Mixed Facts (all strategies taught):

Homes for Facts (HCPSS-adapated resource)
Magic Square (HCPSS-adapated resource)
Number of the Day Mat (HCPSS-adapated resource)
Sums of 6 Triangle (HCPSS-adapated resource)
Sums of 26 (HCPSS-adapated resource)
Alien Addition (student-facing resource)
Math Limbo (Greg Tang student-facing resource, pictured below)
Numskil (Greg Tang student-facing resource)
Strike it Out (student-facing activity)
Smart Subtract Puzzles (print resource)

Independent Practice

These resource sheets can be used for independent practice or homework. They are intended to reinforce procedures and concepts. They should not be used as a source of direct instruction or whole-group practice.

Back to Top

Learning Targets

Recall facts that add and subtract within 20.
Use mental strategies to recall a fact when a fact can't be recalled quickly.

Notes about assessing basic facts:

It is essential to limit the number of timed-tests administered to students. Timed-tests should not be administered more than a few times per quarter at most.
Alternatives to timed-tests include interviews and observations.

Learning targets identify what students should be able to do. The resources below can be used to measure student understanding of the standard.

Assessment Tasks

These tasks align with the learning targets for the standard. They can be combined with other tasks for extended assessment opportunities. Teachers/students are not expected to complete all these tasks.

Back to Top