How to play

ARPE GAME is an online game for exploring perimeter and area and practising estimation. The aim is to estimate the perimeter or the area of the polygon shown, using the unit of measurement given. The goal is not an exact answer, but learning to estimate well from a unit of measurement. On the start page you choose PERIMETER or AREA mode and the difficulty level. At level 1 only triangles and quadrilaterals appear, and the estimate is a whole number. At level 2 polygons with 3 to 8 sides appear, and the estimate is a number with one decimal place.

PERIMETER

In PERIMETER mode, each round shows a polygon and, at the top right, a unit of measurement. The aim is to guess the perimeter of the polygon: an exact measure does not matter, the point is to learn to make reasonable estimates. The unit changes every time, so that students get used to the fact that the perimeter depends on the unit of measurement.

After the estimate of the perimeter is entered in the box, the real perimeter and the player's error appear. More precisely, the real perimeter is given as an interval, because the class should get used to the fact that every measurement has a margin of error: rather than exact values, we speak of confidence intervals.

Even if the first rounds bring big errors, students gradually become familiar with the game and develop an eye for the perimeter. At level 2 the interval of the result, and so the player's estimate, is more precise, with numbers with one decimal place.

AREA

In AREA mode the polygon sits on a square grid: each square is 1 square unit (u²). The player estimates the area of the polygon by counting, more or less precisely, the squares it covers.

Here too, after the estimate is entered, a screen shows a confidence interval for the real area and the player's error.

As in PERIMETER mode, level 1 uses whole numbers, while level 2 also uses tenths.