NVR: shape codes with figures

A free preview from the Athena Learning Library — the same lesson registered students learn from.

In this lesson: Decode a letter code where each letter position stands for one feature of a pictured figure.

Before you start

Secret codes swap letters for meanings, like one emoji standing for one word in a text message. Here, each letter position stands for one feature of a figure.

Watch it happen

Crack a shape code

Code examples: a dark grey hexagon with 1 dot inside has code YNR; a light grey circle with 1 dot inside has code KVR; a black diamond with 2 dots inside has code JPF; a black circle with 2 dots inside has code KPF. Target figure: a light grey hexagon with 2 dots inside with an unknown code.

Every figure carries a three-letter code, and each letter position stands for one feature of its figure. The figure at the bottom is the target — its code is the question mark.

Step 1 of 5

The idea

In a shape code, each figure is given a short code, usually two or three letters. Each position in the code always stands for one feature of the figure. The first letter might stand for the shape, the second for the shading, and the third for the size, but you must work out which is which.

Use this routine. First, find two figures that look the same in one way and compare their codes: the letter that stays the same matches the feature that stays the same. Next, find two figures that differ in only one feature: the letter that changes tells you that position's job. Keep a little key as you work, for example 'second letter: black or white'.

Once your key is complete, build the target figure's code one position at a time, or decode a given code back into a description. Do not guess from a single figure, because one figure alone cannot tell you which letter means what. Comparisons are the evidence, so always use at least two figures before deciding.

Worked example

Every figure in the picture carries a three-letter code, and each letter position stands for one feature of its figure. The figure at the bottom is the target — its code is the question mark. Work out the target's code.

Code examples: a dark grey circle with 1 dot inside has code UKM; a white hexagon with 1 dot inside has code ZBM; a light grey triangle with 2 dots inside has code TLP; a light grey hexagon with 2 dots inside has code ZLP. Target figure: a white circle with 2 dots inside with an unknown code.

Compare the example figures that share the target's shape, the circle: they all begin with U, so letter 1 gives the shape — U = circle.
Now the shading. The target is white, and figures shaded white carry B in position 2, so letter 2 gives the shading — B = white.
One position left: it counts the dots. The target has 2 dots, which is letter P.
Build the code letter by letter: U for the circle, B for white, P for the dots — UBP.

Answer: UBP — U for the circle, B for white, P for 2 dots.

Try one yourself

Using the same code as the worked example, what is the code for the figure in this picture?

The figure is a dark grey hexagon with 2 dots inside.

Watch out

Guessing a letter's meaning from one figure alone; a letter is only pinned down by comparing two figures.
Mixing up code positions — the 1st, 2nd and 3rd letters each keep the same job in every code.
Assuming the letters stand for the first letters of English words; P stands for black here, so always use your worked-out key.

Quick check

Try these on your own first — then reveal each answer.

1. Using the same code as the worked example, what is the code for the figure in this picture?

The figure is a white circle with 1 dot inside.

2. A new code puzzle. What is the target figure's code?

Code examples: a dark grey pentagon with 2 dots inside has code ACK; a light grey square with 2 dots inside has code SJK; a black triangle with 1 dot inside has code EGR; a black square with 1 dot inside has code SGR. Target figure: a light grey pentagon with 1 dot inside with an unknown code.

Practise this concept

Reading is the first step — the concept sticks when your child answers questions on it. Registered students practise graded questions for this lesson, with instant marking and worked explanations, and the lesson is marked complete in their progress.

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