For the past two weeks, I have been working with my grade ones on area. I think it has been my most successful unit so far, so I thought I would share it with you. I based most of my lessons on the information regarding measuring area with non-standard units in Marian Small's book "Making Math Meaningful."

Day 1
I started by doing a three-part lesson. Normally I would start with a formal diagnostic assessment, but since this unit wasn't going to make it on to the report card, I just made some observation notes while they worked. We made a chart to review the important things we need to remember when measuring: all units need to be the same size and shape, and there can't be any spaces between our units. This activated their prior knowledge from doing linear measurement in December. I then introduced some new learning by adding that area is when we measure the whole flat surface of an object. I instructed them to measure the surface of their desk with a partner.

While they worked, I circulated around the room and asked open-ended questions, such as "Tell me why you picked that unit." When they were finished, I recorded each measurement on a chart and they signed their names. A few groups picked a unit that was too small, such as linking cubes or small tiles. I helped them figure out their areas using some "big kid" math (multiplication) so that it wouldn't take all day to measure and count their units.

Day 2
The next day, we continued where we left off by doing part three of the three-part lesson. We discussed as a class the measurements we made and how we figured it out. We also discussed why we all got different measurements and which units were the best choices for measuring the area of our desks. This part of the lesson served as part one (activating prior knowledge) for my next activity. Small states that it is important to have students measure and compare different objects using the same unit. I had selected 6 different blocks to measure. I asked them to compare the blocks and estimate the order from biggest to smallest area. Some were easy to figure out, but there was some argument for others about which one was biggest. I recorded our estimate on the board, then we decided as a class what the best unit would be to measure the blocks. It took a little bit of prompting to get them thinking about using the same unit for all of the blocks. Once we decided what we would use (tiles), I split them up into groups of three and handed out the blocks. The larger or more challenging blocks (ones with curves) were given to my stronger students.

Again, I circulated to ask questions and help groups work through any problems they were having. When all but one of my groups was finished, I asked everyone to gather around my last group to help them. They had a very large block, almost the size of a desk in area. We all helped lay the tiles all over it with no spaces or gaps, then I helped them figure out a strategy to count them. We counted how many tiles there were for the length and width. It was 22 tiles by 11 tiles. One student suggested counting by 20's because that is close to 22. I said that was a good idea, but we don't know how to count by 20's very well. That's when another student suggested counting by 10's because it's close to 11. I thought that was a better idea because we know how to count by 10's very well. So, with my help, we counted by 10's all the way across the block to get up to 220. Then I told them we still need to add on the last row that we didn't count. We counted by 1's, adding on to 220, until we got up to 242 tiles. They were so proud that they could count up to such a big number!

Once we knew the area for all of our blocks, we recorded the measurements on the board and put the blocks in order. We then compared it to our estimate. We had done a pretty good job, but there were a few that were different than what we thought. We also discussed the area of the blocks that had a curve in them and why they were difficult to measure accurately. We talked a little about how to count half units, but they are not quite ready for that concept; I think they need more work with fractions first. That wrapped up our second day on area.

Stay tuned for the next few lessons....

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