Lesson 2

Addition Facts I Know

Est. Class Sessions: 1–2

Developing the Lesson

Reviewing Strategies. Direct students to remove the Addition Facts I Know page from their Student Activity Book. Ask students to work with their partner to study the chart and find any patterns they notice.

After students have had several minutes to study the chart, ask:

X
  • What information does this chart give you? (Possible response: It has the addition problems we are learning.)
  • Look at the problems in the first column, what do you notice about these problems? (Possible response: They all are adding zero to another number.)
  • What strategy can you use to solve each of these problems? (Possible response: When you add zero to a number the answer will always be the other number.)
  • What do you notice about the other problems on the chart? (Possible responses: All the problems in the second column are plus one. The problems in the third column are all plus 2. In the fourth column the problems are all plus 3. Most of the problems in the top row are doubles. Most rows and columns get shorter and shorter.)

Have each student choose different problems from the chart and take turns explaining the strategy he or she would use to solve each problem with their partner. As students are sharing their strategies, listen to their explanations and ask questions to clarify, as needed. See the Sample Dialog.

After students have had time to talk about their strategies with their partners, use your observations to encourage students to share their thinking with the whole class.

Record the Addition Facts I Know for Groups A and B. Provide each student with a set of the Addition Flash Cards for Groups A and B. Students can use the Sorting Flash Cards Board from Unit 6 Lesson 2, or a copy of the Sorting Flash Cards Board Master can be provided to each student, as needed. Tell students that they will work with their partner to practice their addition facts using their flash cards. Use the display of the Addition Facts I Know page from the Student Activity Book, the Sorting Flash Cards Board Master, and the demonstration set of flash cards to review how students will sort their cards into three piles: Facts I Know Quickly, Facts I Can Figure Out, and Facts I Need to Learn.

One student from each pair will turn over his or her flash cards one at a time, solving the problem on the card. His or her partner will check to make sure the answer is accurate. The student will place the card on the sorting board after deciding if the problem is a fact they know quickly, a fact they can figure out, or a fact they still need to learn. If a student is having difficulty with a fact, encourage them to use the strategy suggested on each card. After sorting all of the flash cards, the student circles all of the facts on the cards he or she knows quickly on the Addition Facts I Know chart. The second partner then follows the same procedures to practice his or her flash cards.

X

Students will use the Addition Flash Cards: Groups A and B and the Sorting Flash Cards Board to self-assess their progress toward demonstrating fluency for the addition facts in Groups A and B [E12].

After both students have sorted their flash cards, they should continue to practice the cards in the Facts I Can Figure Out and Facts I Need to Learn piles.

X

This dialog is a discussion of different strategies students use to solve the addition facts in Groups A and B.

Jacob: I can solve all the problems that are plus one really fast because I know the answer is always going to be the next number.

Frank: I don't know what you mean by the next number.

Jacob: Well, when I am adding 1 + 7, I know the answer will be 8 because eight is the next number after seven.

Teacher: Jacob, I think I hear you saying that when you are adding one to a number, you think about the number and then count one more. Frank, can you use Jacob's strategy to add 1 + 8?

Frank: That's easy, one plus eight equals nine, since nine is the next number after eight.

Teacher: [moving to another pair of students] Shannon, what problem did you choose to solve?

Shannon: I solved 5 + 5 = 10. I just thought about the ten frames. There are two rows of five in each ten frame so I know 5 + 5 = 10.

Teacher: Luis, how can you use 5 + 5 = 10 to help you solve 4 + 5?

Luis: Since four is one less than five, the answer for 4 + 5 will be one less than the answer for 5 + 5. So the answer will be nine.

Teacher: Ana and Jackie, what problems did you choose to solve?

Ana: I solved 7 + 2. I thought about 7 in my head and then I counted 8, 9 to show that I added 2.

Jackie: I solved 3 + 4. First I thought about 3 + 3 = 6 and then I counted one more to find 3 + 4 = 7.

Teacher: Jackie, can you explain why you thought about 3 + 3 to help you solve 3 + 4?

Jackie: Since 4 is one more than 3, the answer for 3 + 4 will be one more than the answer for 3 + 3. I already know 3 + 3 = 6, so I used that to answer 3 + 4 = 7.

Student Guide:
Student Activity Book: 237
X
SG_Mini
+
Master: