Un site de France pour l'enseignement des mathématiques, avec des leçons (cours), exercices (avec correction), et exercices répétitifs de calcul mental. Plusieurs fichiers sont disponibles aussi en format PDF.

« Tout élève qui souhaite s'entraîner peut trouver dans ce site des exercices corrigés correspondants à sa classe.
Les niveaux 6e, 5e, 4e et 3e couvrent l'ensemble du programme. Il n'y a ni compétition ni enjeu. Une solution est disponible à tout moment. Ce n'est le plus souvent qu'une solution parmi d'autres.

*Sauf indication contraire, il faut donner la réponse des exercices interactifs, s'il s'agit d'un nombre décimal, avec une virgule. Dans les exercices répétitifs, les nombres sont générés par l'ordinateur, il faut écrire les décimaux avec un point à la place de la virgule.*

Les exercices et les résumés de cours sont signalés de la façon suivante :

-Un résumé du cours : En géométrie, les images mobiles ou les animations flash permettent de visualiser les notions abordées.
-Exercice corrigé : Des exercices pour s'entraîner, avec les corrections disponibles à tout moment. Mais d'abord il faut chercher ...
-Exercice interactif corrigé: On peut répondre directement sur l'ordinateur, mais une feuille de papier et un crayon sont le plus souvent nécessaires pour faire l'exercice entièrement.
-Exercice répétitif : calcul mental : Entraînement au calcul mental sur les techniques basiques à acquérir en mathématiques.

Attention : il faut toujours commencer l'exercice par "recommencer' ou "nouveau calcul" , l'exercice affiché à l'écran n'est qu'un exemple. Il n'est pas à tester ! »

A web page and interactive applet showing the ways to calculate the area of a rectangle. The user can drag the vertices of the rectangle and the other points change automatically to ensure it remains a rectangle. A grid inside the shape allows students to estimate the area visually, then check against the actual computed area. The text on the page gives three different ways to calculate the area with a formula for each. The applet uses one of the methods to compute the area in real time, so it changes as the rectangle is reshaped with the mouse. A companion page is http://www.mathopenref.com/rectangle.html showing the definition and properties of a rectangle Applet can be enlarged to full screen size for use with a classroom projector. This resource is a component of the Math Open Reference Interactive Geometry textbook project at http://www.mathopenref.com.

An interactive applet and associated web page that show the definition and properties of the bounding box of a polygon or set of points. The bounding box is used in other entries to find area using the so-called box method. The grid, coordinates and calculations can be turned on and off for class problem solving. The applet can be printed in the state it appears on the screen to make handouts. The web page has a full definition of a bounding box when the coordinates of the points defining it are known, and has links to other pages relating to coordinate geometry and a worked example. Applet can be enlarged to full screen size for use with a classroom projector. This resource is a component of the Math Open Reference Interactive Geometry textbook project at http://www.mathopenref.com.

The purpose of this lesson is to explore quadrilaterals.

Included is a YouTube video to support Grade 5 Blended Learning Math - Unit 6.3: Geometry - Investigating Quadrilaterals.

The purpose of this lesson is to investigate angles in a quadrilateral.

Included is a YouTube video to support Grade 6 Blended Learning Math - Unit 4.7: Measurement - Angles and Polygons: Investigating Angles in a Quadrilateral.

A web page and interactive applet show how to compute the length of the diagonals of a rectangle. A rectangle is shown that can be resized by dragging its vertices. As you drag, the diagonals are continuously recalculated. Text on the page explains calculation. For those who prefer it, in a formula that is given. Applet can be enlarged to full screen size for use with a classroom projector. This resource is a component of the Math Open Reference interactive geometry reference book project at http://www.mathopenref.com.

An interactive applet and associated web page that illustrate the properties the 'Golden Rectangle' whose sides are in the 'golden Ratio' of 1 : 1.618 : 1. The applet shows a golden rectangle whose vertices a re draggable. When dragged the rectangle changes to remain in the that shape. The web page discusses some properties of a golden rectangle and where it appears in art. Applet can be enlarged to full screen size for use with a classroom projector. This resource is a component of the Math Open Reference Interactive Geometry textbook project at http://www.mathopenref.com.

The lesson begins by introducing Olympics as the unit theme. The purpose of this lesson is to introduce students to the techniques of engineering problem solving. Specific techniques covered in the lesson include brainstorming and the engineering design process. The importance of thinking out of the box is also stressed to show that while some tasks seem impossible, they can be done. This introduction includes a discussion of the engineering required to build grand, often complex, Olympic event centers.

A web page and interactive applet show how to compute the perimeter of a rectangle. A rectangle is shown that can be resized by dragging its vertices. As you drag, the perimeter is continuously recalculated. Text on the page explains that the perimeter is the sum of the sides. For those who prefer it, in a formula that is given. Applet can be enlarged to full screen size for use with a classroom projector. This resource is a component of the Math Open Reference interactive geometry reference book project at http://www.mathopenref.com.

A web page and interactive applet showing the definition and properties of a rectangle. The applet shows a rectangle where the user can drag any vertex. The other points then move in such a way that the figure remains a rectangle at all times. A control to hide the details allows a classroom discussion where students can try to infer what the properties are as it is reshaped by the discussion leader. Text on the page has the formal definition and properties of the rectangle with links to related pages. A companion page is http://www.mathopenref.com/rectanglearea.html showing the ways to calculate the area of a rectangle Applet can be enlarged to full screen size for use with a classroom projector. This resource is a component of the Math Open Reference Interactive Geometry textbook project at http://www.mathopenref.com.

An interactive applet and associated web page that show the definition and properties of a rectangle in coordinate geometry. The applet has a rectangle with draggable vertices. As the user re-sizes the rectangle the applet continuously recalculates its width, height and diagonals from the vertex coordinates. Rectangle can be rotated on the plane to show the more complex cases. The grid, coordinates and calculations can be turned on and off for class problem solving. The applet can be printed in the state it appears on the screen to make handouts. The web page has a full definition of a rectangle when the coordinates of the points defining it are known, and has links to other pages relating to coordinate geometry. Applet can be enlarged to full screen size for use with a classroom projector. This resource is a component of the Math Open Reference Interactive Geometry textbook project at http://www.mathopenref.com.

An interactive applet and associated web page showing how to find the area and perimeter of a rectangle from the coordinates of its vertices. The rectangle can be either parallel to the axes or rotated. The grid and coordinates can be turned on and off. The area and perimeter calculation can be turned off to permit class exercises and then turned back on the verify the answers. The applet can be printed as it appears on the screen to make handouts. The web page has a full description of the method for determining area and perimeter, a worked example and has links to other pages relating to coordinate geometry. Applet can be enlarged to full screen size for use with a classroom projector. This resource is a component of the Math Open Reference Interactive Geometry textbook project at http://www.mathopenref.com.