Comparing Costs


This is a level 2 number and statistics, level 3 algebra activity from the Figure It Out series. It relates to Stage 5 of the Number Framework.
A PDF of the student activity is included.

Achievement Objectives
NA2-1: Use simple additive strategies with whole numbers and fractions.
NA3-6: Record and interpret additive and simple multiplicative strategies, using words, diagrams, and symbols, with an understanding of equality.
S2-2: Compare statements with the features of simple data displays from statistical investigations or probability activities undertaken by others.
Student Activity

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Specific Learning Outcomes

use additive strategies to add numbers

Description of Mathematics

Number Framework Links

Students at stages 5 and 6 should be able to use various strategies to solve the problems in this activity independently. (See the table of NDP material on page 4.)

Required Resource Materials
Pet-care costs sheet (see Copymaster)

FIO, Levels 2-3, Financial Literacy: The Real Cost of Pets, Comparing Costs, page 8

A calculator

A classmate


Financial understanding
In this activity, Teigan investigates the set-up costs for a dog. A person who does this, for any pet or interest, is more likely to be financially able to cope with ongoing costs. The discussion questions focus on the difference between items that are essential and those that are not, the fact that people can’t always afford what they want, and that there are ways to meet needs and then wants without spending too much money.
To do this activity, the students need to have some understanding of animals’ requirements and be able to distinguish between “wants” and “needs”.
The students apply thinking skills while collecting, organising, and analysing information using their pet-care costs sheets. They communicate their findings by using what they have recorded.
For question 2b, the students could discuss ways of reducing the costs of the items on the pet-care costs sheet. However, they need to look at other costs that might occur with their ideas. For example, if they go to the river to get stones, they need to consider the extra cost of time and travel. They could also discuss with elderly
relations or neighbours what items their childhood pets had and what has changed over time.

Students doing the extension activities suggested below could use a computer for graphing and could communicate via Internet, fax, or email.
Further investigations: mathematics and statistics; social sciences
The students could extend their work by doing one or more of the following:
• Research the life expectancy of various animals and then compare the costs of owning the animals over these lengths of time and the effect on the overall cost of each animal. This could be graphed and compared, for example, in a pie graph, using set-up costs, ongoing costs, and needs for each animal.
• Research items we now buy that used to be home-made or not used at all, for example, soap, toothpaste, butter, clothes, toys. The students could also discuss this with elderly relations or neighbours. This could also extend to a study of other countries’ consumerism or lack of consumerism.
• Research sustainable ways of owning pets. In what ways could the costs of pets be reduced, taking the environmental impact into account? For example, is using a plastic litter box for kittens better for the environment than reusing cardboard boxes? Questions such as this would make good debate topics.

Social Sciences Links
Achievement objective:
• Understand how cultural practices reflect and express peoples’ customs, traditions, and values (Social Studies, level 2)
The students could conduct a social inquiry in their class, school, and wider community and then share what they have learned.

Other Cross-curricular Links
Science achievement objective:
• Life processes: Recognise that all living things have certain requirements so they can stay alive (Living World, level 2)
The students could research what different animals need in order to stay healthy, for example, dietary, exercise, shelter, or entertainment requirements.
Technology achievement objective:
• Brief development: Describe the nature of an intended outcome, explaining how it addresses the need or opportunity. Describe the key attributes that enable development and ev aluation of an outcome (Technological Practice, level 3)
The students could:
– design and make a mouse tunnel or a toy for a dog or cat
– design and make something for their pet that uses recycled or reusable materials.

Answers to Activity

1. a. $668 (plus the cost of buying the dog and other costs such as registration,
microchipping, vaccinations, and so on)
b. As indicated in the question, all the answers below are based on lowest costs on the petcare costs sheet.
Cat: $221 (plus the cost of buying the cat, neutering, vaccinations, and so on)
Rabbit or guinea pig: $180 (plus the cost of buying the animal)
Mouse or rat: $192 (plus the cost of buying the creature)
Fish: $127–$190 (depending on the type of fish and the food required by that fish)
Frog: $186
Turtle: $227
2. a. Discussion will vary. For example, it’s unfair to a dog or cat if you don’t use flea
treatment and worming pills; a bean bag for a dog is a luxury!
b. Discussion will vary. For example, dogs are quite happy sleeping on an old blanket; you don’t have to have special feeding bowls as long as you keep the dish just for the dog or cat; you can make toys for animals to play with (for example, cats like playing with a piece of paper attached to a string; you can train dogs to chew only old shoes that you give them and to leave your new ones alone); some people treat their pets for fleas and worms using inexpensive herbs in the pet’s bedding and diet.
Reflective question
Answers will vary. Some of the questions you might ask yourself include:
• Can you afford to buy the animal and the necessary items (even using cheaper options where possible)?
• Will you be able to afford the ongoing costs?
• Will you have the time to care for the animal properly?
• Do you really want the animal, and will you want and/or be able to look after it for its whole life? (There’s no point spending money on an animal that you don’t really want and will lose interest in.)
• Can you afford unexpected expenses, such as vet bills or the replacement of items (such as slippers that have been chewed by your dog)?

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