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Proportional Reasoning. Equivalents. Integer Rods. White 1 cm x 1 cm W Red 2 cm x 1 cm R Lime 3 cm x 1 cm L Purple 4 cm x 1 cm P Yellow 5 cm x 1 cm Y Green 6 cm x 1 cm G Black 7 cm x 1 cm K Brown 8 cm x 1 cm N Blue 9 cm x 1 cm B
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Proportional Reasoning Equivalents
Integer Rods • White 1 cm x 1 cm W • Red 2 cm x 1 cm R • Lime 3 cm x 1 cm L • Purple 4 cm x 1 cm P • Yellow 5 cm x 1 cm Y • Green 6 cm x 1 cm G • Black 7 cm x 1 cm K • Brown 8 cm x 1 cm N • Blue 9 cm x 1 cm B • Orange 10 cm x 1 cm E
Equivalent Rods • Equivalents • How many combinations can be made of each type of rod? • Is there a pattern?
What is the pattern? • How many different ways are there to make Y?
How many different ways are there to make G? • What is the pattern? • Number of Equivalents = 2(n-1), where n is the number of units in a rod • Should you assign your students to find all of the equivalents for K or N?
On a test or quiz you will have to give a semi-concrete model of the rods • It is important that your semi-concrete models be as accurate as you can make them • The letter representing the color of the rod should be placed in each rod’s representation once and only once – see class notes
Equivalent Fractions • How do we represent fractions using integer rods? • Part to whole • Whole changes as necessary to make equivalents • A train is two rods put together • We will ALWAYS use the least number of rods possible to make a representation • Do NOT draw more lines on representations than necessary
One half is W over R: • One half is R over P: • One half is ? over ?: • How many half equivalents are there up to an EE train?
One third is W over L: • One third is R over G: • One third is ? over ?: • How many third equivalents are there up to an EE train?
One fourth is W over P: • One fourth is R over N: • One fourth is ? over ?: • How many fourth equivalents are there up to an EE train?
What rational number does this represent? • What rational number does this represent?
Other Manipulatives • We have just looked at two manipulative that can be used to model rational numbers, there are MANY others • Check out some other electronic manipulative listed under http://ejad.best.vwh.net/java/patterns/patterns_j.shtml and http://nlvm.usu.edu/en/nav/topic_t_1.html