Title
Adding Tenths
Problem Statement
On a calculator, enter the number 0.1. Continue to add 0.1 until you get
0.9. When you add another 0.1, what do you think you will get? Why?
Continue to count to 4 or 5 by tenths. How many times do you have to add
0.1 to get from one whole number to the next? Try counting by 0.01. How
many times do you have to add 0.01 to get from 0.01 to 0.1? Which is
faster, counting by tenths to 10 or counting by hundredths to 1?
What real-world application can we use as a context for this
exploration?
Problem setup
This problem involves closure of addition
using rational numbers. We are exploring the addition of tenths
and hundredths and how rapidly these numbers approach whole numbers.
For example, counting by tenths to 4 or 5.
Plans to
Solve/Investigate the Problem
Because of my existing mathematical maturity
(Thanks Sarah), I recognized right away that it is quicker to count by
tenths than it is to count by hundredths. And then also because of this,
I know that there are the same number of incremental steps when counting
to 10 by tenths as there are counting to 1 by hundredths. My plan
to explore this includes an Excel spreadsheet to demonstrate the
incremental increases.
Investigation/Exploration of the Problem
Please click here to
view my Excel spreadsheet.
Extensions of the
Problem
The problem asks where this type of
exploration may be applied in a real-world application. It would
be very easy to ask students to make the connection of counting by
tenths and hundredths using dimes (tenths) and pennies (hundredths).
Author & Contact
Teresa Johnson
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