Illuminations: Let's Learn Those Facts

# Let's Learn Those Facts

## Wrapping up the Unit

 In this final lesson of the unit, students display their knowledge of properties of objects for sorting and creating patterns. They also demonstrate an understanding of commutativity and model addition and subtraction of whole numbers using different representations.

### Learning Objectives

 Students will: practice the addition facts they have learned so far identify the facts that they have left to learn

### Materials

 Crayons Number cubes Paper Counters Collect the Counters Activity Sheet

### Instructional Plan

 Place students in groups of up to four students, and provide each group with three number cubes, at least 64 counters, and a copy of the Collect the Counters activity sheet. Have each student pick a row, write his or her name next to it, and cover each number in that row with a counter. Then have the players take turns rolling the three number cubes, finding the sum of the numbers, and removing the counter from the sum. Allow the students to play a sample game as you circulate to be sure they understand how to play. In this game, there are 16 possible sums that can result when three number cubes are tossed, namely 3‑18. Obviously, some of these sums are most likely than others. As students roll and attain various sums, they remove the counters from the game board. For instance, if a student had rolled four times and obtained sums of 7, 11, 13, and 17, their game board would look like this:     You can adjust the rules for winning depending on how much time you would like students to spend playing this game. In the longest version, play until one student has removed all of the counters. (Note that the probability of rolling a 3 or an 18 is only 1/216, so it may take a while for these rolls to appear.) In shorter versions, play until a student removes 3, 4, or 5 counters in a row. (Asking students to identify the counters in a row that were removed by the winner can lead to a good discussion about probability and why some sums are more likely than others.) Introduce the students to the Hungry Frog, which provides an opportunity for students to practice facts and develop fluency in recalling them. (When you click on "Click Here to Change Options," students may select from among the four binary operations—addition, subtraction, multiplication, division—and the game may include the use of negative numbers.) Remind students to click on the frog whose lily pad has the accurate sum for the math fact that appears on the bug. Clicking on the frog makes it "hungry" and enables it to eat the bug with the correct fact. When a player clicks on a bug that has the accurate fact that matches the sum on the frog, he eats that bug and earns points for the player. The object of the game is to catch the correct bug before the bonus ball vanishes to win bonus points. [If students play in pairs or small groups, it may be necessary to specify a number of facts that constitute a turn for each player. This provides a more equitable distribution of play.] Have students document the beginning and ending bonus points and subtract the difference to determine the total number of points they collect in each turn. To conclude the lesson, assign the students to play either the computer game or the number cube game.

### Questions for Students

 What is the sum of 4 + 3? What other number pairs have the same sum? [7; 0+7, 1+6, 2+5.] What pair of numbers has a sum of nine? Are there any others with that sum? [0+9, 1+8, 2+7, 3+6, 4+5.] What do you know about 3 + 7 if you know the sum of 7 + 3? What property is this? [The sum for both is 10; the commutative property.] What numbers sum to three? To eleven? To five? [0+3, 1+2; 0+11, 1+10, 2+9, 3+8, 4+7, 5+6; 0+5, 1+4, 2+3.]

### NCTM Standards and Expectations

 Number & Operations Pre-K-2Understand the effects of adding and subtracting whole numbers. Develop fluency with basic number combinations for addition and subtraction. Develop and use strategies for whole-number computations, with a focus on addition and subtraction.
 This lesson prepared by Grace M. Burton.

1 period

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