First Grade - November 3rd - November 7th, 2008

Our first graders are still working on addition problems. We're looking for students who can use the strategy of Counting On to add numbers together. To help students with this strategy, we are playing games with a number cube and a dot cube. When students add the two numbers together, they will not be able to Count All the dots because one of the cubes only has numbers. For example, imagine that you roll a 4 on the number cube and a 3 on the dot cube. A student has to start at 4 and count 3 more to get a total of 7. This idea of Counting On is much more efficent than Counting All the items in two groups.

Another strategy for addition is to use combinations already known to figure out new combinations. If a student knows that 5 + 5 = 10, they can reason that 6 + 4 = 10 because you just take one away from one of the 5's and give it to the other 5.

We are also working on the idea of finding all the addition combinations that equal a given number. Students are told that they have 7 items. Some of the items are blocks and some of the items are marbles. What are all the different combinations of blocks and marbles? We want students to develop a systematic way of finding all the combinations. Start with 1 block and 6 marbles, then move to 2 blocks and 5 marbles, then 3 blocks and 4 marbles, etc. Students should also realize that they can find opposites. If they have 3 blocks and 4 marbles, they can also have 4 blocks and 3 marbles.

Finally, we will start to study subtraction this week. It will be interesting to see the different types of strategies students use to solve subtraction problems.