Doubles, Halving, Doubles + 1 FactsUnit of Study: 13Global Concept Guide: 1 of 3

Content DevelopmentWe continue to add to our students’ repertoire of math facts, this time focusing on doubles facts. Because both addends are the same, there is no need to address the commutative property, so this fact set is quite small—just eleven doubles fact in all. And because students have already explored and practiced +0, +1, +2, they really only need to learn seven doubles facts.Students will use their knowledge of the doubles facts to build an understanding of doubles-plus-one facts. Additionally, halving will be explored as the inverse relationship to doubling.Providing many experiences to build models of the structure of these number concepts are crucial. Flash cards should not be the only tool to build fluency. You can also consider using a Fact Log to encourage at home practice.

Day 1 Whole group lesson: Magical Doubles

Math Stations:1. Double Ten-Frames: Have students work with partner to find

doubles ten-frame cards, find the sums, and record number sentences.

2. I Spy Doubles: Students search for double dominoes (the same number of dots on each side). They write the matching addition equations.

3. Doubles Memory: Students match doubles facts with the correct sum. If they match then the child keeps the set, if not they return them to the same spot, facedown and her turn is over. Play continues until all cards are matched.

Day 2Halving to solve: Students are solving real world problems using halving.

Math Stations:1. Bean Bag Subtraction: Create a floor mat with a vinyl shower

curtain liner or table cloth, marking nine sections, each containing an even number from 2-18. Students take turns tossing a beanbag and calling out the number it lands on as well as the half (10, 5 is half of 10). Students record the subtraction sentence in their math journal.

Day 3 Exploring the Facts: Doubles and One More

Math Stations:1. Near-Doubles Trains: students will need 10 linking cubes of two

different colors, a 1-9 spinner. Students spin the spinner to determine how many cubes of one color should be linked to make a train. They then make a second train, of a different color, using that number of cubes plus 1 more. Students link the two trains together and determine how many cubes there are in all. Students record what they have modeled by coloring the train recording sheet and writing the near-doubles equation. Then, they take apart the train and spin again to create a new near-doubles train.

2. Math Fact Sort – Overall facts sorted by categories

Monitoring Progress Individual Conferencing:

As students work to master their using doubles facts, taking the time to confer with individual students allows you to assess their progress and focus them on specific goals. As the students in your class are engaged in Math Stations, invite individual students to meet with you to review their most recent Fact Check and graph their results. Examine blank or incorrect math facts. Ask students which facts are difficult for them to remember. Provide tips and reminders to help students master those facts. Praise each student for the facts she does know and encourage each student to continue reviewing the unknown facts.

Gathering Data Through Observation Frequently move through the room observing partners as they explore using-

doubles facts. Listen to their discussions to gain insight into their understanding and mastery. Jot down observations to help plan interventions, adjustments to lessons, or task modifications.

Building Automaticity Once students have explored the concept of doubling, halving, and near-

doubles and observed and discussed patterns, it is time to check their progress.

Literature for your Classroom Library

Double the Ducks By Stuart J. Murphy

Martha Blah Blahby Susan Meddaugh

Fish Eyes by Lois Ehlert