Call the students together and ask for a volunteer. Have that student roll a single number cube and record the number that came up. Now ask what number must be rolled for a total of six. [If a six was rolled the first time, the student should report that no further rolls are necessary.] Then have the student record the number sentence on the board [6 + 0 = 6.] Repeat with other volunteers.
Ask what addition fact would represent a roll of one and a roll of five. [1 + 5 = 6.] Then ask what addition fact would represent a roll of six and no further rolls. [6 + 0 = 6.] You may want to mention that zero is known as the additive identity, and you may want to ask students why they think that zero has this name. [The sum when any number is added to zero is itself, so it is "identical."]
Now ask the students to take out their Facts I Know activity sheets they began completing in the previous lesson, Finding Addition Patterns. Ask what addition facts they can be sure of, if they know that any number plus zero is the number that they started with. Have the students fill in those facts on their personal addition charts. Then ask them what happens when they add one to a number. [They may suggest it is like counting on to the next number.] If they can answer correctly, have them enter these facts on their charts as well. This will significantly reduce the number of facts that need to be learned separately. Note that as a student begins to identify patterns, they will be able to complete large portions of their addition charts. A partially completed chart is shown below.
|
+
|
0
|
1
|
2
|
3
|
4
|
5
|
6
|
7
|
8
|
9
|
|
0
|
0
|
1
|
2
|
3
|
4
|
5
|
6
|
7
|
8
|
9
|
|
1
|
1
|
2
|
3
|
4
|
5
|
6
|
7
|
8
|
9
|
10
|
|
2
|
2
|
3
|
|
|
6
|
|
|
|
|
|
|
3
|
3
|
4
|
|
|
|
|
|
10
|
|
|
|
4
|
4
|
5
|
6
|
|
|
|
|
|
|
|
|
5
|
5
|
6
|
|
|
|
10
|
|
|
|
|
|
6
|
6
|
7
|
|
|
|
|
12
|
|
|
|
|
7
|
7
|
8
|
|
10
|
|
|
|
|
|
16
|
|
8
|
8
|
9
|
|
|
|
|
|
|
|
|
|
9
|
9
|
10
|
|
|
|
|
|
16
|
|
|
To give students a chance to practice the sums to six, assign them to pairs and give each pair two number cubes. Tell them that the goal of the game they will play is to make sums of six. Ask them to take turns rolling the number cubes and giving
themselves a tally mark each time the sum is six. Allow them time to play the game, then call them together and tell them that you will name a number less than six and they should raise their fingers to show how many more are needed to make six. Play this game several times, then ask volunteers to list on the board all the ways they can get six when they roll a pair of number cubes. [0 + 6, 1 + 5, 2 + 4, 3 + 3.] Invite the students to add as many of these facts as they know by heart to their personal addition charts.
To conclude this lesson, have students record, on paper, a picture of two number cubes showing a sum of six.
