Conversion cousins - Part 1
This is a level 4 number link activity from the Figure It Out series. It is focused on finding fractions, decimals, and percentages of whole numbers and knowing fraction, decimal, and percentage equivalents. A PDF of the student activity is included.
About this resource
Figure It Out is a series of 80 books published between 1999 and 2009 to support teaching and learning in New Zealand classrooms
This resource provides the teachers' notes and answers for one activity from the Figure It Out series. A printable PDF of the student activity can be downloaded from the materials that come with this resource.
Specific learning outcomes:
- Find fractions, decimals, and percentages of whole numbers.
- Know fraction, decimal, and percentage equivalents.
Conversion cousins - Part 1
Achievement objectives
NA4-5: Know the equivalent decimal and percentage forms for everyday fractions.
Required materials
- Figure It Out, Link, Number, Book Three, "Conversion cousins", page 2
See Materials that come with this resource to download:
- Conversation cousins activity (.pdf)
Activity
To do this activity, students need to be familiar with decimals, fractions, and percentages and the relationship between them.
Students who have trouble with this might find it helpful to complete a table like the one following. Encourage them to use what they already know as the starting point, such as 50% and 1/10.
They can use the completed table to find the answers, although the challenge always needs to be:
- Can you work it out without looking at the table?
Percentage |
0% |
10% |
20% |
30% |
40% |
50% |
60% |
70% |
80% |
90% |
100% |
|---|---|---|---|---|---|---|---|---|---|---|---|
Decimal |
0 |
0.1 |
0.2 |
0.3 |
0.4 |
0.5 |
0.6 |
0.7 |
0.8 |
0.9 |
1.0 |
Fraction |
0/10 |
1/10 |
2/10 |
3/10 |
4/10 |
5/10 |
6/10 |
7/10 |
8/10 |
9/10 |
10/10 |
The students also need to understand how to add amounts in different forms. For example, to answer question 1b, they need to work out 1/10 + 20% + 0.15 + 0.25.
Discuss with the students how they might do this. Some may prefer to convert all the amounts to fractions with a common denominator (10/100 + 20/100 + 15/100 + 25/100), some may convert them all to percentages (10% + 20% + 15% + 25%), and others may convert them all to decimals (0.1 + 0.2 + 0.15 + 0.25).
1.
a. $28
b. Yes. The other presents cost $10 (Fergus’s brother), $20 (Percy’s dad), $15 (Dewey’s dad), and $25 (Dewey’s mum). This adds up to $70, leaving $30 for Grandad’s present.
2.
|
Fergus’s brother |
Percy’s dad |
Dewey’s dad |
Dewey’s mum |
Grandad |
Total cost |
|---|---|---|---|---|---|---|
Fergus |
1⁄10 |
20⁄100 (or 1⁄5) |
15⁄100 (or 3⁄20) |
25⁄100 (or ¼) |
28⁄100 (or 7⁄25) |
98⁄100 (or 49⁄50) |
Percy |
10% |
20% |
15% |
25% |
28% |
98% |
Dewey |
0.1 |
0.2 |
0.15 |
0.25 |
0.28 |
0.98 |
Cost |
$10 |
$20 |
$15 |
$25 |
$28 |
$98 |
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