Oh, Fractions!

We are working on Sarah’s Pre Algebra Road Trip this week.  Students start off by choosing 5 cities to travel to around the US.  They measure the distances, then they use the scale on the map to find the actual distances between the cities.  Because the distances were obviously not whole numbers, the proportions that the kids had to set up involved fractions.  So we needed to do a quick review of how to multiply with fractions.  We began by talking about fraction decimal equivalents.  Since we rounded to the nearest 1/4, this should be easy, right?  Ha.  So I began by asking the world’s most dangerous question. 

“What is 1/4 as a decimal?”

And I get the typical, yet still shocking and absolutely horrifying…

1.4?      0.14?  

No.  No. NO.  NO!

Next came my least favorite thing that students do.  If their first few answers were wrong, let’s just yell out anything!  We must happen upon the right answer eventually, right?

3?  1.5?  6.2?

How do students get to 7th grade having so little knowledge of basic number sense?  I obviously want them to understand how to convert between fractions and decimals, but really my major concern is that students have no idea that 1.4 means 1 whole and part of another.  Which means if it was a mixed number it would still have a 1 as the whole number, then a fraction to represent the part.  So if I just have a fraction, then we must have a 0 in front of the decimal point, because there is not a whole number part.

Let’s fix this, fellow teachers!

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