Noves fora.

Abstract

The nines test or better known popularly as nines away is a method that was widely used in the last century, being found in didactic books and multiplication tables. People who often worked with math used this method to quickly check their calculations. The nines test or better known popularly as nines away is a method that was widely used in the last century, being found in didactic books and multiplication tables. People who often worked with math used this method to quickly check their calculations. At the end of the twentieth century with the evolution of technology and the emergence of other methods of verication, the nines out was no longer presented in textbooks, and thus gradually ceased to be presented in the classroom, but only as a social context. The rst records about nines abroad were in the ninth century in Arabic arithmetic, being traversed throughout Europe, until reaching the Brazilian textbooks. Understanding the math that is involved in this method helps us understand why it is no longer used in textbooks and so at school. Nines out is the rest of dividing a number by 9, being in the range of 0, ..., 8, another way to nd nines out of a number is by adding all its digits and dividing it by 9. This method has aws, so it is one of the reasons that is no longer seen in textbooks and consequently in schools, being only in the social context.