The Math Forum

Search All of the Math Forum:

Views expressed in these public forums are not endorsed by NCTM or The Math Forum.

Math Forum » Discussions » Education » math-teach

Topic: el fractions etc
Replies: 0  

Advanced Search

Back to Topic List Back to Topic List  

Posts: 8
Registered: 12/6/04
el fractions etc
Posted: Aug 12, 1995 10:32 AM
  Click to see the message monospaced in plain text Plain Text   Click to reply to this topic Reply

Nancy, I almost garantee your 4th graders can make connections if you use
this only takes about one week. Give me your address and
I'll be happy to share a more detailed description and the pertainent
worksheet organizers. Tonna

I use a constructivist approach to introducing the many forms of fractions.
Basing the opening activity on prior knowledge of money (decimals and
fractions) and grades (percentages and fractions), I have my fourth and
fifth graders work out decimal equivalents for halves, thirds, fourths,
fifths, sixths, etc. through twentieths (we skip thirteenths and a few
others that are not common). Then students use the decimal fractions to
find fractions which are equivalent and look for and "discover" that the
numerator/denominator relationship is constant for a given group of
equivalent fractions--a pattern! Finally, students extend the pattern they
have found to generate more equivalents to the lists already started (more
that equal 1/2, etc.) and use new ratios to generate new lists 1:50, 1:100 etc.

How can we get from 1/2 to ,50? We think: dollar (1.00)
divided by 2 is .50. So, could 1/2 be another way of writing 1 divided by
2? It is! ...another algorithm is "discovered"!

Next, students develop a chart showing relationships between:

fraction, division problem, decimal fraction, per cent, and ratio
1/2 = 1 divided by 2 = .50 = 50% = 1:2

We write word problems that show these connections. often ending up with
three forms in the same problem and play with diagrams, circle graphs and
manipulatives to develop number sense in this area. Then we USE this all
year! Students receive fraction grades (21/24) and are responsible for
figuring decimal then percentage equivalents...what fraction of the class
is in band?...If only 17 students are getting hot lunches and 6 of them are
getting milk in addition to the 4 brown baggers getting milk, what is the
ratio of milk drinkers to non-milk drinkers today--is the percentage of
milk drinkers going up since our nutrition study?.........

Yes, we do use calculators to find decimal fraction equivalents to
fractions. At that point I want students to get excited about the
division/fraction/decimal relationship...excitement with kids means go
fast! Later, many equivalents are memorized (really, internalized) and we
may work the division with paper/pencil or use calculator depending on time
and objectives.
Tonna Kershul
8-11 yrs. mixed age class

Point your RSS reader here for a feed of the latest messages in this topic.

[Privacy Policy] [Terms of Use]

© The Math Forum at NCTM 1994-2017. All Rights Reserved.