As students gathered on the dark blue rug in Room 38, Class 2 Co-Head Teacher Kym Mendez announced, “Okay, time to turn off your Español brain and turn on your math brain!” (Students had just finished a lesson with LS Spanish teacher Isamar Rosado.) Ms. Mendez then proceeded to write 80-40 = ? on the whiteboard.
Students quickly raised their hands, offering the correct answer of 40. “How do you know?” prompted Ms. Mendez. One student explained that she knows if you subtract four from eight, you get four, so that helped her figure out the answer. Next, Ms. Mendez made it a bit trickier by writing the number sentence: 800-410 = ?
Again, students answered correctly, noting that once you subtract 400 from 800, you simply subtract another ten to reach the answer of 390.
“Alright, mathematicians, you’re nice and warmed up!” said Ms. Mendez, pivoting to the morning’s lesson. “We’re going to use our math skills to contemplate and calculate. Contemplate means to think deeply about something.”
To kick off the lesson, which was part of their complex geometry unit, students watched a silent video from their spots on the rug which featured a structure made of multiple, colorful 3-D cubes shown from various angles. “What did you notice?” their teacher asked once the video finished.
Several students offered astute responses, such as ‘The shape gets smaller as it gets higher,’ ‘At the top, there’s only one green cube visible,’ and ‘If you look from above, it’s a X shape.’
Ms. Mendez explained that the goal was to find how many total cubes were in the structure using a ‘short cut.’ “How can we be strategic?” she asked, noting that while they could simply count them all, that would be a tedious and time-consuming effort. “Also, I want you to calculate how many there are of each color.” (Each row contained a specific color cube.)
The students began with estimations – which their teachers gently reminded is an educated guess and not a random choice. Then, they spread across the room in pairs or solo to determine the answer.
“Remember, mathematicians think about how they know the right answer,” said Co-Head teacher Kim Tran, encouraging students to show their thinking on the page.
For the next fifteen minutes, students worked attentively, their teachers on hand to help with any questions they had. If they finished early, there were “extension sheets” available that provided additional complicated problems for them to solve.
At the sound of a soft chime, students returned to the rug for discourse – an opportunity for students to lead their peers through their mathematical approach.
After taking her spot at the front of the room, one student explained that she added by color to determine the total. For example, 4+4 (red cubes) = 8. Then she added another 8 red cubes located on the opposite side of the structure to arrive at 16. She continued this process and ultimately landed on the correct answer of 45 cubes.
Another student utilized a different method. She determined that the rows were getting smaller by four. Therefore, once she found the total number of red blocks, she subtracted each color by four. Lastly, she added up all colors together to determine the total.
“There are tons of different ways to solve,” concluded Ms. Tran, applauding each student’s unique approach. “Really nice job today, friends! Now it’s time for snack!”