|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Hickory
Grove Press
3151 Treeco Lane
Bellevue, IA 52031
Ph/Fax: 563 583-4767 |
|
e-Mail Us! |
| |
|
|
 |
|
Hickory Grove
Press |
|
|
REAL
WORLD ALGEBRA
Understanding
the Power of Mathematics
|
|
Algebra
is often taught abstractly with little emphasis on what
Algebra is or how it can be used to solve real
problems. |
|
|
|
|
|
Chapter 6: Algebra and
Proportions |
|
Algebra
and Proportions
Janelle loved her pet flea.
She taught it to do tricks like pulling a man with a
silk thread around its neck. Her flea was an
amazing insect that could pull objects hundreds of
times heavier than its own weight and jump many
times higher than its height. As sometimes
happens when children are proud of their pets, she
started bragging at school.
Janelle told all her friends that
if people could jump like fleas, they could jump 500
feet high. How this was an amazing story that
on one really believed, but everyone knew how proud
Janelle was of her pet, so they didn't believe her.
Then one day in algebra class,
Janelle's math teacher asked the class if anyone
believed the story about how high people could jump
if they had legs like fleas. Instead of
answering, all the children started laughing.
"Of course not, that is a silly
story." one of the children finally said.
Janelle asked the teacher if she
could prove that what she said was true.
Janelle then went to the blackboard and set up two
ratios. |
|
|
 |
| Janelle put in the n
because she was trying to find out how high a person
could jump. Janelle knew that when you have a
fraction on each side of the equation, you can
cross-multiply to make the equation easier to solve. |
|
|
A
smile came over Janelle's face when she realized
that she was right. She had proven that
if humans could jump like fleas, they could jump
over 500 feet high. The rest of the class was
shocked, but Janelle had used a powerful part of
math to prove her point. She had used algebra
with ratios and proportions. |
|
|
|
|
|
