What we need, what we want

Paper packet. Every task here also exists on screen, where it is checked automatically; answers written on paper are not assessed by Nydus. When you are back at a device, enter your answers there.

1. What you will learn

2. Starting point

3. Words for this lesson

4. Start with the situation

Imagine a class is preparing a short drawing activity. The teacher says each person needs a sheet of paper and something that makes a mark. A colored cover would be a welcome extra, but the drawing activity can happen without it. Paper and a working pencil meet requirements of this particular activity. The cover meets an additional wish. This example does not tell us everything any person needs in life. It gives us a small situation we can understand and check.

A need is something required for a purpose or for well-being. A want is something someone would like. These ideas can overlap: you can want clean drinking water and also need it. It is a mistake to think that a need must be unpleasant or that something enjoyable cannot help meet a need. Meals can be enjoyable. A warm coat can have a favorite color. The important question is what the item does in the situation, rather than whether someone likes it.

Some needs concern staying healthy and safe. Other requirements belong to a stated activity: a ticket may be required to enter a particular event. The event itself is not therefore a basic need. Keep those two questions separate. In our exercises, the activity's requirements are supplied. You will use that information, count what is available, and find what is missing. You will not be asked to judge another person's real life from a short description.

Words such as necessary and optional help us make this distinction. Necessary means the stated purpose cannot be met without the item or a suitable replacement. Optional means the purpose can still be met without that extra. Optional does not mean worthless. It simply tells us something about the requirement we are checking.

Term	What it means
Need	Something required for a purpose or for well-being.
Want	Something a person would like; a person can want something they also need.
Requirement	A condition the stated activity must meet.
Optional	The stated purpose can still be met without this extra.
Usable	Able to meet the requirement in the case.
Substitute	Another resource that meets the same requirement.

Another way: One need can have different ways to meet it

Suppose a notice must be readable. A dark pencil on light paper might work. So might a dark marker on light card. The requirement is a readable notice; one particular brand of marker is not automatically required. Before saying that a supply is missing, ask whether an available substitute does the job. A substitute is another way of meeting the same requirement under the stated conditions.

Now change the task. The notice will be placed outside in rain, and the instructions require a waterproof display. Ordinary paper by itself may no longer work. A protected paper notice might work if its cover is waterproof. The answer changed because the task changed, not because paper is always good or always bad. This is why a list of objects alone cannot tell us which ones are necessary.

Keep the size and quality requirements too. If four people each need one clean cup, one large bowl is not an acceptable substitute when the instructions say everyone must have a separate cup. If sharing is allowed, a different arrangement might work. Do not invent permission to share or refuse permission that the case actually gives. Read the supplied rule before counting.

A useful habit is to say the purpose aloud, name its requirement, and then match the resource to that requirement. For the drawing activity, the purpose is drawing, the requirement is a way to make a visible mark, and a working pencil meets it. A broken pencil without a sharpener does not. A new decorative box does not replace the missing way to draw, even though it may be attractive.

Another way: Count required items before adding extras

Consider a group with five learners. Each needs one card for an activity. There are three usable cards on the desk. Count the required cards first: five. Count the usable cards next: three. The difference is two, so two additional cards are needed. Writing the two counts separately prevents us from answering a different question, such as how many objects are on the desk altogether.

Suppose there are also six stickers. Adding three cards and six stickers gives nine objects, but it does not give nine cards. Stickers cannot fill the card requirement unless the case says they can. The labels on quantities matter. A total that mixes different kinds of objects can be arithmetically correct and still fail to answer the question.

The missing amount is the required count minus the available usable count when the required count is larger. If there are more usable cards than required, nothing is missing. There is a remainder instead. For example, seven cards for five learners leave two cards after everyone receives one. We do not say that the group is missing minus two cards. We say that zero are missing and two remain.

We can check an answer by putting the parts back together. Three available cards plus two missing cards equal the five required cards. If our answer had been one, three plus one would give only four. The check would reveal the mistake. Checking is especially useful when the story includes an optional extra, because an extra can distract us from the exact resource the activity requires.

Another way: An extra does not cancel an unmet requirement

A group needs four readable maps for four pairs of walkers. It has two readable maps and ten colorful badges. The badges do not make the two missing maps disappear. They serve a different purpose. To prepare the walk under the stated rule, the group still needs two additional readable maps or an allowed replacement. Counting more desirable objects is not the same as meeting each requirement.

This does not prove that badges are bad or that walkers should never have them. It identifies what remains unfinished in this plan. Economics often begins by making a choice clear before evaluating it. We can describe the required resources, the resources available, and the extras people would enjoy. A later lesson asks what to do when the same limited time or money could provide different things.

The requirements also belong to particular people or tasks. If one pair already has its map, giving that pair a second map does not provide a map to a different pair. A group total can hide how resources are distributed. In a simple one-per-pair case, we check both that there are enough usable maps and that each pair receives one. Equal totals alone do not guarantee a complete plan.

Be careful about promises of future supplies. Two maps that might arrive tomorrow do not count as maps available for a walk this morning. If the walk is tomorrow and the delivery is confirmed, the case may allow us to include them. Use the time stated in the question. An item can be useful at one time and unavailable at the time it is needed.

Another way: People and purposes differ

A person's needs can depend on their situation. Someone may need a ramp to reach a room, information in large print to read a notice, or a quiet place to hear instructions. The fact that another person does not need that resource does not show that it is an unnecessary extra for everyone. Begin with the supplied requirement and the person's circumstances rather than assuming your own experience fits every person.

We should also distinguish a preference from a claim about somebody else's needs. Saying 'I prefer the blue bag' reports a preference. Saying 'the equipment needs a waterproof bag' states a requirement that can be checked against the equipment and conditions. A blue bag could meet that requirement, or fail to meet it. Color alone does not settle the waterproofing question.

In a real group, asking people what they need can reveal information that is not visible. In our small written cases, that information is provided. If it is not provided, say what is unknown instead of making up a personal circumstance. Good reasoning includes noticing when a confident label would go beyond the evidence.

Describing an item as optional for one task does not rank the person who wants it. Someone's enjoyment matters, and a choice can reasonably consider it. The distinction helps us keep different reasons visible. First establish what the stated purpose requires. Then identify the extras that could add comfort, beauty, fun, or another benefit. We can compare the use of resources more clearly when we have not mixed all those reasons into one undivided list.

Another way: Build a short, checkable explanation

A clear explanation has three parts: the requirement, the available resources, and the result of comparing them. For example: 'Each of six groups needs one tray. There are four usable trays. Two more trays are needed because four plus two makes six.' This explanation shows where the answer comes from. Saying only 'two' leaves the reader to guess whether you mean trays, groups, or optional decorations.

When there are several requirements, make one row for each. A model-building session might need five bases and five connectors. With five bases and three connectors, the bases are sufficient and two connectors are missing. Combining the counts into eight objects would hide the connector problem. Separate rows keep unlike resources separate and make the final check easier.

Finally, state the limit of the conclusion. Finding two missing connectors tells us what this plan lacks. It does not tell us which shop to use, what price would be fair, or whether the whole project should go ahead. Those questions need more information. Learning to answer the question supported by the case, without adding an unsupported judgment, is a useful first step in economic reasoning.

5. Preparing a community drawing table

A community center prepares a drawing table for eight visitors. The organizer's plan requires one usable sheet and one working pencil for each visitor. Sharing pencils is not allowed in this activity because everyone will draw at the same time. The table has six usable sheets and nine working pencils. It also has twelve decorative stickers, which visitors may use after making their drawings.

Start with the paper requirement. Eight visitors need eight sheets; only six are ready. Eight minus six equals two, so two sheets are missing. Check by adding: six ready sheets plus two additional sheets would provide eight. Do not add stickers to the paper count. They are decorations, not drawing sheets under this plan.

Next check pencils. Eight are required and nine work. There is no pencil shortage: give one to each visitor and one remains. This surplus pencil does not solve the missing-paper problem because a pencil cannot replace the sheet on which someone draws. Keeping the two rows separate reveals both facts.

The organizer finds two more sheets in a drawer, but one is torn into small pieces that the activity instructions do not allow. Only one additional usable sheet has been found. Seven usable sheets are now ready and one is still missing. The attractive sticker collection remains an optional extra. This conclusion is about the supplies for a stated activity; it does not judge the visitors' preferences or tell the organizer what to buy. Before the activity begins, the organizer can check the actual supplies again and confirm that each visitor receives the required items.

6. A tempting mistake

An optional extra cannot replace a required resource unless it actually does the needed job. Count usable items of each kind separately.

7. Three cards for five learners

8. More cups than the activity requires

9. Two requirements and a damaged item

10. Four maps for seven pairs

11. Guided practice

Five learners require one card each; three usable cards are ready. Give the missing count and the count remaining after the requirement is met. If there are too few, none remain.

12. Guided practice

Complete the supply check: six teams require one base each and four usable bases are ready.

13. Guided practice

A drawing session requires paper and a working pencil. Ribbons and stickers are optional decorations. Match each item to its role in this stated session.

14. Practice

Eight groups each require one tray. Four usable trays are ready and no sharing is allowed. Give the missing count and the count remaining after the requirement is met. If there are too few, none remain.

15. Practice

Six people each require one pencil. Eight working pencils are available. Give the missing count and the count remaining after the requirement is met. If there are too few, none remain.

16. Somewhere new

A repair workshop requires one clean cloth at each of nine work stations. Six clean cloths are ready. Colorful labels cannot replace cloths. Give the missing count and the count remaining after the requirement is met. If there are too few, none remain.

17. Lesson test

Lesson test: one question per skill, one attempt each, no hints. Your answers are checked when you submit.

18. Test question

Seven visitors each require one readable handout. Seven readable handouts and five decorative badges are ready. Count handouts only. Give the missing count and the count remaining after the requirement is met. If there are too few, none remain.

19. What you can do now

Explain how to identify a supplied requirement and calculate what is missing or left over. Show a fresh example and check its result.

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	Your result
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	Your result
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