8
th
Grade
Mathematics
Unit 2:
Exponents
Excerpts from Georgia Department of
Education Webinar August 1, 2012
melissa.stewart@hallco.org
August 2012
Warm-Up
An ant has a mass of approximately 4 x 10-3
grams and an elephant has a mass of
approximately 8 x 105 grams.
How many ants does it take to have the
same mass as an elephant?
melissa.stewart@hallco.org
August 2012
What’s the main idea of Unit 2?
• Developing deep understanding of
rational and irrational numbers,
square and cube roots, and with
operations of exponents and
scientific notation.
• Developing deep understanding
and fluency with solving linear
equations.
melissa.stewart@hallco.org
August 2012
Concepts & Skills to Maintain from Previous Grades
 Computation with whole numbers and decimals,
including application of order of operations
 Solving equations
 Plotting points in four quadrant coordinate plan
 Understanding of independent and dependent
variables
 Characteristics of a proportional relationship
Websites to help with the above:
www.aaamath.com
http://www.arcademicskillbuilders.com/
http://www.professorgarfield.org/pgf_home.html
http://multiplication.com/
melissa.stewart@hallco.org
August 2012
Enduring Understandings from this Unit
 Square roots can be rational or irrational.
 An irrational number is a real number that cannot be written
as a ratio of two integers.
 Every number has a decimal expansion, for rational numbers
it repeats eventually, and can be converted into a rational
number.
 All real numbers can be plotted on a number line.
 Rational approximations of irrational numbers can be used
to compare the size or irrational numbers, locate them
approximately on a number line, and estimate the value of
expressions.

is irrational.
 Exponents are useful for representing very large or very
small numbers.
 Properties of integer exponents can be use to generate
equivalent numerical expressions.
 Scientific notation can be used to estimate very large or very
small quantities and to compare quantities.
 Linear equations in one variable can have one solution,
infinitely many solutions, or no solutions.
melissa.stewart@hallco.org
August 2012
Examples & Explanations
1.
melissa.stewart@hallco.org
August 2012
2. You have a coupon worth $18 off the purchase of
a scientific calculator. At the same time, the
calculator is offered with a discount of 15 %, but
no further discounts may be applied. For what tag
price on the calculator do you pay the same amount
for each discount?
melissa.stewart@hallco.org
August 2012
3.
Marco and Seth are lab partners studying bacterial growth. There were
2000 bacteria at the beginning of the experiment. They were surprised to
find that the population of the bacteria doubled each year.
a. What was the size of the population after 1 hour? After 2, 3, and 4
hours? Explain your answers.
b. Assuming the population doubled every hour before the study began,
what was the population of the bacteria 1 hour before Marco and
Seth started their study? What about 3 hours before? Explain your
answers.
melissa.stewart@hallco.org
August 2012
 The student edition for Unit 2 can be
found at
https://www.georgiastandards.org/C
ommon-Core/Pages/Math-6-8.aspx
On the left side, please look under
mathematics, 6 – 8. Then, the right
side has a pull-down menu to access
the units.
 Additional parent guides will be
posted to the parent resource page on
http://www.hallco.org/boe/index.ph
p (right had menu) as they become
available.
melissa.stewart@hallco.org
August 2012