^^Numeri razionali.

Campo dei nr razionali, costruzione.

The Development of Multiplicative Reasoning in the Learning of Mathematics (Google eBook) 1994

Rational Number Project

Rational numbers are not simply ordered pairs of whole numbers

pag viii

6 costruzioni dei nr razionali

1. part to whole comparison
2. decimal
3. ratio
4. indicated division (quotient)
5. operator
6. measure of continuos or discrete quantities

Misconception: multiplication makes bigger and division makes smaller.