Subtraction Centers

Last week we took some time to slow down and review some of what we have learned so far this year. We have spent the past month learning about addition and subtraction. At the end of our unit on subtraction, we began looking at fact families as a way to tie them together. 

Since we learned so much information in such a short amount of time, I wanted to give the children a chance to reflect on and practice what we had learned before we moved on. Centers are a fun way for children to practice information and a great way to make sure everyone is engaged in learning!

The first center was a center called "bump". The children took two ten-sided dice and rolled them. Then they made a subtraction sentence out of those numbers. After they figured out what their difference would be, they covered it up on the game board. If their partner got the same number, they could "bump" them off of their number. If the same partner got the same number twice, they could double up on their counters and block off that number so they got to keep it. The player with the most numbers covered at the end of the game wins. This was a great way for the children to practice counting on because 11 and 12 were on the dice and they cannot count these on their fingers. This is a strategy we will spend more time on as we begin looking at numbers up to 20. 

Another center was the "Parts of a Whole" game that went along with our unit in enVision math. The children took turns spinning two spinners and then had to find the difference between the two numbers, very similar to the bump game. Once they found the difference, they covered up the basket that matched their number. Again, the player with the most spots covered at the end wins. One difference in this center was that the children were given counters to use to figure out their subtraction stories. This is a great tool for children to use when they are adding or subtracting because it is concrete and allows kinesthetic learners to physically move the counters as they work through the problem. 

Another center was "Fact Family Triangle". At this center, the children rolled two dice and then had to figure out the sum of the two numbers and use all three numbers to make two addition sentences and two subtraction sentences. We have started moving the numbers around and making sure that we still have the same "equals", sum, or product and this reinforced this concept very well. If the students just put their numbers in a random order, I would have them actually use their fingers or counters to work through the problem so that they could understand why their number sentence was not correct. This helps the children know what to do no matter where the numbers or symbols are in the number sentence. 

The last center that we had for the week was a domino activity. In this center, the children had to take out a random domino, draw it on their paper, and then make two different addition sentences using the numbers and two different subtraction sentences using the numbers. This was great practice for fact families. It also helped students remember how they can move numbers around in a number sentence. They have the commutative property for addition down pretty well...they know that 2+3=5 and that 3+2=5, but the subtraction ones are a little trickier!

We concluded the week by using honey nut cheerios to make fact families during Munchie Math on Friday. This was a great and tasty review of what we had done earlier in the week.