To reinforce their number sense, strengthen mental math and challenge them a little, I pointed to my hundred's chard on the wall. I told them that adding by teens numbers was easy if they could create a strategy. We were going to practice adding by 13 starting with the number 7 and see if we could see a pattern, so it is easier to figure out the next sum.
We began and students were stumbling. I kept pushing ...33, 46, 59,72 etc. I stopped them. Then I started saying it... 72, 82 and 3 is 85, 85, 95 and 3 is 98.
I waited a minute to see if they noticed what I was doing. I asked if they could hear my thinking as I was adding. One student's hand shot up and he explained. "You were adding ten and then three out loud." I asked why they thought I pulled the ten out.They told me that it was because adding ten is easier.
I said " Bingo!"
I wrote the strategy on the board:
Whenever you add a tens digit number, pull the tens out, add it and then add the ones.
It's really easy to understand how the denominator represents the parts of the whole using dominos and this Domino Effect SB Template. My students also used this Domino Effect Practice Sheet to help them keep their drawings organized.
I brought up the SB File for whole class instruction. This lesson is quick and a great way to practice drawing equivalent fractions on a bar model. Students came up to the SB to help me draw lines to define the denominator and also shade in the numerator values. It was a straightforward and easy!Domino Effect Classroom SB File
Students were given their practice sheets and piles of dominoes within reach on their desks. They practiced independently. I roved the classroom and visited students as they worked. I assisted some by guiding them as we were defining the numerator to shade in. Then, they transitioned into creating an equivalent fraction as I had instructed on the SB. I left the SB classroom file up for a visual representation.
The rest of the class time was spent choosing dominoes to draw on their sheets. Each student was able to finish about 10 dominoes.
To wrap up the lesson today, I asked students for any "aha" moments. One student shared that he had created two equivalent fractions of two different dominos. He had picked a domino with 2/4. He drew 4/8 under that drawing. Then he had picked 4/8 and realized that he could just draw 2/4. So, he did not divide up the 8th into 16ths to create the equivalent fraction. This is an example of him demonstrating MP 1,2, 7 & 8 all at once. He found structure, reasoned quantitatively, and used repeated reasoning. Great! Many students shared that they liked using the template much better and that the lesson was fun.