If I Know This Then I Know Addition Worksheet
This if I know this then I know addition worksheet helps 1st grade students use turnaround facts to solve sums within 20, with an answer key included for quick, confident checking.
$6.97
Want this one free?
Tell us where to send it and it’s yours — no card, no catch.
One free resource per teacher. We’ll also send free teaching ideas each week — unsubscribe anytime.
Free teacher account · no credit card
Membership
Get every game, song, & printable
- Every game, on any device
- 6,500+ resources
- Assign online with HFT Classroom
Then $39.97/year · cancel anytime · See plans
- Instant digital download
- Printable PDF + answer key
- Made by real teachers
Teacher / Family membership
Teaching is easier with every resource
One membership for your whole year: 6,500+ worksheets, games, songs and videos for Preschool–6th, for your classroom or homeschool.
- Unlimited printables & downloads
- Every game, on any device
- Assign online with HFT Classroom
- Cancel anytime
Teacher / Family membership · 3 days free
Yearly
Monthly would be $119.64 a year
$3.33/month
Billed $39.97 once a year
You save $79.67 every year
Start My 3 Free Days$0 today · cancel anytime
Monthly
$9.97/month
Flexible, month to month
Yearly is just $3.33/mo. Switch and save $79.67
Start My 3 Free Days$0 today · cancel anytime
About this resource
Description
Knowing one addition fact can unlock another. This If I Know This Then I Know Addition Worksheet helps first graders see that the order of the addends does not change the sum. When a child knows that 8 + 5 = 13, they also know that 5 + 8 = 13. This idea is called the commutative property of addition, and many teachers call these pairs turnaround facts.
The worksheet shows seven addition facts with sums from 10 to 17. Students solve the first fact under the heading “If I know…” and write the sum in the box. Then they follow the arrow, look at the same two numbers in the other order, and solve the turnaround fact under “…then I know!” As they work, students notice that both boxes in each row hold the same answer. This 1st grade addition worksheet works well as morning work, a math center, homework, or a quick check after a lesson on addition strategies.
What’s Included
- One page with seven fact pairs, each with a turnaround fact to solve
- Addition facts with sums within 20 for extra fact practice
- A full answer key on a second page for quick checking
Why It Helps Kids Learn
First, turnaround facts cut the number of facts a child has to memorize nearly in half. Second, students build number sense when they see that a sum stays the same no matter which addend comes first. Third, the clear left-to-right layout gives children a simple routine they can use on any addition problem: solve one fact, then use it to solve its partner.
Ideas for Teachers and Parents
Before starting, show the idea with two groups of blocks, then swap the groups and count again. After students finish the If I Know This Then I Know Addition Worksheet, ask them to write their own fact pair and explain it to a partner. You can also cover the second column and have children predict the sum before they write it.
Related Resources
What teachers say
Reviews
Write a review, earn store credit
Get 25¢ in credit for every approved review of a resource you’ve downloaded, played or purchased — up to 15 a month. Credit applies automatically to your membership payments, so your reviews can help pay for your membership.
Honest reviews only — any star rating earns the same. Program rules
Log in to write a review and earn store credit.
This adding and subtracting within 20 worksheet gives first graders mixed addition and subtraction fact practice with a helpful number line. Includes a complete answer key for quick, no-prep math review.
This adding and subtracting to 20 worksheet gives 1st graders ten mixed addition and subtraction equations to solve within 20. Answer key included — perfect for quick, no-prep math fact practice at home or school.
This Adding Word Problems with 3 Numbers Worksheet helps 1st graders add three single-digit numbers using fun story problems about ducks, apples, and more. Includes a complete answer key for quick, no-prep addition practice.
This Adding 3 Whole Numbers Within 20 Worksheet gives 1st graders twelve problems to practice adding three single-digit numbers for sums up to 20. Includes a complete answer key for fast, no-prep addition practice.
This Ten More Ten Less Worksheet gives 1st graders eight quick problems to find ten more and ten less than a two-digit number. Includes an answer key for fast, no-prep place value practice.
A first-grade commutative and associative properties worksheet where students solve ten addition problems by adding the numbers in any order or group. Includes an answer key and a handy reminder box for no-prep math practice.
This counting on to add worksheet helps 1st graders start from the bigger number and count forward on a number line to twenty. An answer key is included, so checking work takes seconds.
This adding tens and ones worksheet helps 1st graders build two-digit numbers with base ten blocks and column addition. Includes an answer key for quick, no-prep place value practice at home or school.
This Adding In Any Order Worksheet helps 1st graders see that 3 + 4 and 4 + 3 always match, using picture groups first and quick fact flips second. Answer key included, so practice takes minutes to check.
This Word Problems Adding 3 Numbers Worksheet gives 1st graders five short stories to solve by writing and adding a three-number equation. Answer key included, so practice with sums to 20 stays quick and stress-free.
This finding the missing number worksheet gives first graders focused practice solving for the unknown number in addition and subtraction equations within 20. Includes an answer key — a quick, no-prep way to build number sense and fact fluency.
This writing addition sentences worksheet gives 1st graders six picture-friendly word problems to solve by filling in each addition number sentence. Answer key included — perfect for no-prep addition practice at home or in class.
Reviews
There are no reviews yet