Title
Units of Seven
Problem Statement
Find the units digit of
7^{189}. Determine a general rule for finding the units digit of 7^{n},where n is any whole number.
Problem setup
What number is in the ones
place when I evaluate 7^{189} ?
Plans to
Solve/Investigate the Problem
I plan to use a spreadsheet using 7^nth
and look for a pattern.
Investigation/Exploration
of the Problem
I noticed that the units digits form a pattern of 1, 7, 9, 3. This is a
four digit repeating pattern. I then divided 189 by 4,
I had a remainder of 1. Thus I thought 1 would be the units
digit of 7^{189}.
After class discussion I realized that 7^0 =1 is not part of
the pattern. Thus the pattern is 7, 9, 3, 1. The units digit will be a 7.
Author & Contact
Dottie Mitcham
Link(s) to resources, references, lesson plans, and/or other
materials
Link 1
Link 2
U
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