Crazy numbers for crazy people

5th Grade Mathematics: chapter 4
Mathematics student’s book page 18: The value of a digit in a big number
(Greek educational system)

 

Math-Girl- 

 

Materials for the lesson

The Teacher has chosen some mathematical problems that involve big numbers. For example with the population of China which is approximately 1.400.000.000 and India which is also approximately 1.300.000.000 inhabitants. Other examples can be the debt of a country, the population of a specific small size animal in a given country, the cost of expensive cars, the numbers of hair on a person’s head etc.

Layout of the classroom

Students form groups and move the desks as to serve the purpose of group work.

Phase 1

Students have already been taught about the significance of each digit’s place in a number and in particular in big numbers (more than 6 digit numbers).

The teacher reads a couple of mathematical problems involving big numbers. These exercises could be from the material already used and taught.

 The teacher asks the students to form groups and make space in the classroom. These groups are given specific time to come up with “alternative mathematical problems”. These “alternative mathematical problems” have to use big numbers but not necessarily in a form which makes sense. The idea is to end up with funny stories involving mistakes with these big numbers.  

Phase 2

Students work in groups while the teacher moves around the classroom and helps out.

Phase 3

Students read their stories to the rest of the class. Some possible scenarios one could come up with could be: a) the purchase of a car at the price of 0.000.100 euro or b) Greece having a bigger population than that of China, in numbers Greece 11.000.000 and China 000.000.000.140.

The idea is to understand the value of a digit through its place in a big number and the absurdity which occurs in one makes a mistake.

Another option involves the dramatization of a given story produced by the students. The purchase of a Ferrari in the price of 000.300 euro en vive can cause some big laughter…