Math Fact Strategy Seed Ideas
Addition and Subtraction
(based on Teaching Student-Centered Mathematics, 2006)
Doubles Strategy
The “doubles strategy” is used when the two addends in the number sentence are the same,
hence the double. Extensive practice with visualizing numbers as dots and other pictorial
representation is especially helpful with this strategy. Students should use the commutative
property to be able to apply this strategy to twice as many facts, even though the addends are
the same.
Seed Idea: Doubles Strategy Cards
 Addition: Fold the card over on the dotted line so it is covering one of the doubles
addends. Ask the students what number they see without counting, and ask them how
many dots you could have if you doubled that. Make the connection to multiplication and
repeated addition.
 Subtraction: You can write the total number of dots on the back on the flap, so when it
is hiding one of the addends. Students will see how many dots there are on the card and
how many are showing. Students will use the doubles strategy to decompose the number
to determine the missing addend.
Seed Idea: Doubles Turn around Cards
 Addition: Show the turn around card to students and have them tell you the number
sentence that it represents. (6+6=12) Then, turn around the card so that students can
realize they are exactly the same number sentence.
 Subtraction: Take the card and write the sum on the back. Have students decompose
that number as many ways as possible and circle which one of the ways they decomposed
the number is a doubles fact. Flip the card over to check.
Seed Idea: Doubles Flashcards
 Addition: Show the flashcard and have them use the doubles strategy to solve the fact.
This should only be used after extensive work with the meaning of operation and
application of the strategy.
Seed Idea: Doubles Dominos
 Addition: Have the students create cards with the answers to the doubles facts by
using their addition chart to determine a pattern. Students should notice that all
doubles facts sums are even numbers. Once the students have created the cards, they
can match the sum with the doubles domino.
 Subtraction: Give the students subtraction number sentences that use the doubles
strategy. Have them match the number sentence with the corresponding doubles domino.
Seed Idea: Doubles Subtraction Flashcards
 Subtraction: Cut out the flashcards and then fold them on the dotted line. Show the
flashcard and have them use the doubles strategy to solve the fact. This should only be
used after extensive work with the meaning of operation and application of the strategy.
Discuss what matching “think addition” number sentence can be created from the
subtraction number sentence.
Seed Idea: Doubles Strategy Missing Addend Cards
 Addition: Cut out the flashcards and then fold them on the dotted line. Show them the
missing addend card and have them figure out what the missing addend would be. Have
them share what strategy they used to find the missing addend.
 Subtraction: Have them determine the missing addend and tell what the related
subtraction fact would be.
Seed Idea: Doubles Strategy “Think Addition” Cards
 Addition: Cover the bottom number and ask the students what the total number of dots
would be. Discuss what strategies were used to find the answer.

Subtraction: Fold down one of the addends and ask them how many dots are missing.
Have the students share the strategies that they used to determine the missing number
of dots.
Seed Idea: Doubles Visuals
 Addition: Review the doubles visuals with the students and then cut out the doubles
fact and the pictures and have the students match them together.
 Subtraction: Show the students the doubles visual and have them tell you the doubles
addition number sentence and the matching subtraction fact.
Seed Ideas: Doubles Pictures
 Addition: Take a piece of paper and fold it in half and have the students put small blobs
of tempra paint on the left side of the paper and then fold it over while the paint is still
wet. Have them write the doubles fact that is represented.
 Subtraction: Give them a double sum, like 12 and have them put the same amount of
blobs on each side of the paper to represent the doubles fact. Have them write the
subtraction faction (12-6=6) that is represented. Make the connection to fair share and
division.