# Expanded Notation and Comparing Decimals, featuring virtual base ten blocks using Google Docs

Saturday, October 17, 2015
Before I share my activities from this week, I am excited to share that I was asked to co-host a webinar about Google for Education! I will be asked to share and discuss how I use Google within my classroom.  I am looking forward to sharing my ideas and I would love for you all to join the discussion! Here is a link that will allow you to register for the event.

Review of Decimals and Using Base Ten Blocks
To activate prior knowledge and to review what students learned in fourth grade, we started off the week making decimals using base ten blocks.  I started making baggies with bits and pieces of each type of block and then quickly realized, there has to be a better way! And there is! I created a Google Doc that I shared with my students on Google Drive.  Students were able to work together to make decimals using the document I created.  I could toggle back and forth between groups, making  comments and suggestions, all in real time.  I could also see misconceptions and observe students who were not recalling the information from fourth grade.
I allowed the students to work on this for about 10 minutes then we went onto whole group, where we reviewed the base ten blocks and how to make decimals using the blocks.  We took notes in our journals and afterwards students could go back to their groups and apply the knowledge to fix their decimal documents.

While students were working, I could see them fix their mistakes and make the decimals appropriately.  I could also give feedback instantly.

Expanded Notation

The next day we moved onto expanded notation.  Students knew that each place has a value, but I knew they would have trouble connecting that each number is composed of that place value times the digit.  For example: 3.45 would be written as (3x1) + (4 x 0.1) + (5 x 0.01)
I wanted a hands-on way to visually see the process of multiplying the digit by the place value.  I made a set of cards for each place value, from the tens to the thousandths.  I copied the cards using colored paper.  I also made an activity mat that allowed students to record a number and then construct the number using cards.  At the end, students would record the expanded notation at the bottom.  To save paper, I laminated the activity mats and had students use dry erase markers.  To add a fun element, I had students generate numbers using dice.

Comparing Decimals

This is a standard that students should have been taught in fourth grade.  To activate prior knowledge and observe students' current understandings, I asked a simple question on Edmodo.  Using the poll feature on Edmodo, I asked, "Which number is greater? 0.49 or 0.7?"  Often times students who don't remember their place value will suggest 0.49 is greater simply because 49 is bigger than 6.  So this quick 2 minute assessment gives me a ton of knowledge about their current understanding.

Afterwards, we draw and talk about each place value while recording observations and details in our journals.  To allow students to practice, we play a very simple game called Roll Big, Roll Small.  The game is very simple,  Round one, students roll dice to create a number.  The biggest number wins.  In Round two, the smallest number wins, and so on. Since our focus is decimal comparisons, students are creating decimals.

Another fun activity we do as a class, is explore race data.  Again I ask a simple question on Edmodo, using the poll tool.  I ask "If Payson and Madison were running a race and Payson finished the race in 25.67 seconds and Madison finished the race in 25.5 seconds, who won the race?" Many times students think that the biggest number is always the winner, because of that, many vote for Madison winning the race. Before we talk about the answer to the question, we collect some race data of our own.  Using a stop watch I time each child how long it takes to eat a starburst candy.  Almost immediately, students figure out who is winning the eating contest.  We record each time down in our journals.  At the end of the race, once everyone has had a chance to eat a starburst, students put the times in placement order starting with first place.  This really allows them to see that first place is the smallest time and then last place is the biggest time.  At the end of our lesson we look back at our poll on Edmodo.  We talk about who won the race and why.

Next week, we will be taking curriculum assessments on all of our material so far.  I am always a little nervous about the first test, but I think they will do great.

Until next week,
Peace, Love, Math-
Jennifer