4t ESO Notes 2026–27

Maths challenges

Class notes, originally in Catalan. Published challenge by challenge as the course goes on.

Pythagoras, scales, areas of plane figures, conversion factors and percentages to paint a mural.

A cone full of water on the roof: Pythagoras, volume, converting m³ to litres and kilograms, load and a scale drawing.

From the perimeter and width to the length of a football pitch, with a linear equation.

The generating fraction of 0.9 recurring, with an interactive figure to see what happens with infinitely many nines.

Worksheet to prepare for the test on 5 October: percentages, volumes and areas of composite shapes.