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Welcome to my math blog! The purpose of this blog is to help you stay informed about our learning and experiences that have taken place during our math class. I have also included links your child (and you) may want to use in order to supplement math learning in 5th grade.

Friday, November 14, 2014

Comparing and Ordering Decimals

Comparing and ordering decimals was the focus of today's lesson.  We took additional notes today as we learned the process.  I began by having students restate what they have learned about decimals.  They did a very good job!  They reminded me that when moving to the right in our place value system we are dividing by 10.  They explained that we can think of the tenths place as dimes, the hundredths place as pennies, and the thousandths place as an amount smaller than a penny.

I explain that knowing this information would help when it came to comparing and ordering decimals.  I asked that they write the most important rule of working with comparing and ordering decimals:

ALWAYS line up the decimal points!

Next, we discussed using t-charts to help us line up our decimal points.  On the left side of the t-chart is where we place the whole number.  The right side of the t-chart is where we place the decimal portion.  The decimal itself is on the line that separates these two parts of our number.

Once we have placed our numbers on the t-chart we can use place value to compare.  I covered the decimal portion of the t-chart and we focused on the whole numbers.  Today I made it a little easier, all the whole numbers were the same!  Once we realized that the whole numbers were no help in determining which number was larger (since they were all 7s), we moved to the next place... the 10ths place.  Now we were able to look at the three digits in this place.  This is where thinking of 10ths as dimes was helpful.  They realized that a 5 in this place was less than an 8.  Once we determined the smallest digit in the tenths place we moved to hundredths.  Again, thinking of the digits as pennies proved helpful.  Finally, we moved to the thousandths place and compared any remaining digits.

We also discussed that we can "add" a zero to the end of a decimal number to give it an equivalent number of digits to the other numbers being compared.  I emphasized that we can add or take away zeroes at the END of decimal numbers, but NEVER add or remove zeros elsewhere in the number!

Once we finished with our notes, we headed to khanacademy.org to work with our new learning.  It was during this time, that I had an epiphany.... decimals are EASY to work with IF YOU THINK OF THEM AS MONEY!  Every time I had a student who struggled, I went to them and told them to think of the activity as money (even if there were numbers in the thousandths place or larger).  Once I showed this to my classes, things went much more smoothly! 

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