Tuesday, January 15, 2013


Ever wonder about the extra 9 in the cost of a gallon of gasoline at the pump? Here's a real-world activity for middle schoolers which might lead to a deeper understanding of decimals and fractions not to mention producing more educated consumers!

So what does the "raised" 9 mean at the end of $2.99? Some retailers display the extra 9 by writing it as 9/10. Nine-tenths of what? Hey, the cost is still less than $3.00 so that 9 is pretty insignificant, right, kids?

We would hope our youngsters would guess the extra 9 represents nine-tenths of a penny or nine thousandths of a dollar. We would hope...

First I would ask the students or my child or grandchild at home what she thinks the 9 means.  In the classroom, we ask the questions but we are not always obligated to confirm or reject students' replies! Research shows that the consensus of the group is usually correct so trust them and help them to develop more confidence!

So how would you develop this lesson to reinforce decimal/fraction skills and develop deeper understanding of decimals in a practical consumer setting? What are some questions you would ask?

Hey, it's my blog and I don't have to show my way first!

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