What the graph does not print

A missing graph reading can be found when the question supplies a relationship that fixes its value. Your child combines the visible data with a stated total, difference or multiple, rather than estimating the absent reading from its surroundings. This is an application of the MOE Primary 4 outcome on interpreting data. The arithmetic matters, but the first decision is which pieces of information refer to the same quantity.

• Identify what is missing and read every visible value needed for the stated relationship, using the graph's scale and units.
• Recover a hidden value by subtracting the known contributions from a total that covers exactly those contributions and the missing one.
• Use a stated comparison or multiple to connect two readings, writing the meaning of an intermediate answer before using it again.
• Turn a recovered count into a cost when a price per item is supplied, keeping the number of items separate from the amount of money.
• Decide whether a statement follows from the supplied data, and recognise when the information does not determine a unique answer.

When one reading is recovered from a combined total, add it back to all the known readings included in that total. Their sum must reproduce the given total exactly, so a value that merely looks plausible on the graph is not enough.

The set has six Intermediate questions and two Challenge questions. They recover missing information from a total, a difference or a multiple, then may ask for a combined count or a cost. Other Intermediate questions use a best-three score requirement or ask whether a statement follows from incomplete data. Challenge questions use equal item counts or a fixed total of drinks to recover a hidden reading. Ask your child to separate a value that can be determined exactly from a condition that allows several possible values. For a hidden graph reading, first write the relationship connecting it to the known readings; for a statement, test whether every permitted value supports the claim. After an attempt, use the written working to trace which relationship determines the unknown reading. The free biscuit-sales question includes written working, which lets you discuss why recovering the missing week's count comes before calculating the money collected.

Should my child guess a hidden point from the line beside it? Use the information that determines it. A total or a comparison may fix the hidden reading even when its position cannot be read. If the data do not provide enough information, there may be several possible values; your child should not invent a pattern just to choose one.

Why do some graph questions ask about money? The graph may supply a count, while the question gives a price for each item. Your child first finds the relevant count and then calculates its cost. Labelling those two answers separately helps explain why the first answer has an item unit and the second has a currency unit.

How do I help my child judge a statement about data? Ask which readings would prove or disprove it, then check whether those readings are available. A statement can be contradicted by the data, supported by them, or left undecided. Those are different conclusions, and your child needs to explain the conclusion using the actual information supplied.