GAMES THAT LEAD TO THE UNDERSTANDING OF AREAS MEASUREMENT

Measurement of surfaces with arbitrary units

To bring the class to this purpose, the teacher can start by showing the tabletop and the seat of a chair, at the same time asking: "Which piece of wood is larger, this one or that one? Next, the children will be asked children to compare the teacher's tabletop with that of a child's table. In this way different surfaces will be compared, deciding in all cases by simple visual appreciation. Then children can be asked to compare a long surface and narrow with another shorter and wider surface. To help them, the teacher can propose any arbitrary unit, for example rectangular tiles or cardboard. She will then pose the question in other terms, asking: "How many pieces of cardboard do we need to cover this table, or that one? With the help of the teacher, the children put the pieces of cardboard or the tiles until the entire surface is covered (or is, approximately) and they are counted how many have been used in each case.

With these methods, children can gradually acquire the idea that what they measure is the entire surface, and they become able to decide whether one surface is greater or less than another or, simply, to measure a surface based on a certain unit.

Using the square decimeter

Here, too, it is admitted that a unit known to all is necessary, and the teacher presents a "square decimeter" cut out of cardboard or plywood. Children are allowed to handle it and compare it to the units of length they already know. A sufficient number of squares must be available for all children to measure some fairly large surfaces by coating. Children should be carefully placed next to each other by counting the number of them when everything is covered. By this procedure, it is discovered that such a simple shape measures six square decimeters, etc.

The square centimeter

 Proceed exactly as for square decimeters. It should be noted that smaller surfaces must be taken.

Measurement of a surface with two units at a time (decimeters and square centimeters)

The teacher presents a rectangular surface that does not have an exact number of square decimeters, and gives the children two piles of squares, one of decimeters and the other of centimeters. They are encouraged to start measuring with the larger of the two units. Finally it is counted and the result is obtained.

They may discover that 100 small squares the size of the square centimeter fit in the large square, equal to one square decimeter. The teacher can encourage comparisons with smaller units.