Como dizer "prova dos nove" em inglês

Olá galera.. estou com uma dúvida faz uma semana... como se chama aquelas provas que a gente faz na metemática pra saber se as "contas" estão certas em inglês?

Tipo, eu resolvo uma conta de mais.. eu posso fazer a PROVA REAL e a PROVA DOS NOVE..

como se chama isso em inglês?

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5 respostas
Donay Mendonça 22 107 1.6k

Prova dos nove[noves fora]: Casting out nines

Definição em inglês: A method of checking the correctness of elementary arithmetical operations, based on the fact that an integer yields the same remainder as the sum of its decimal digits, when divided by 9. []

Bons estudos!
Valeu mesmo donay....isso ajudou muito mesmo!! Valeu!
PPAULO 6 48 1.1k
Also, "the proof by nine" (La pruef par neuf). Which was, by the way, a matter of an abstract.
By John G. Gosselink.

In Brazil, I learned that it can check all four operations of basic mathematics:
addition, subtraction, multiplication, and division.

=============== ... x/abstract

Gosselink, J. G. (1955), THE PROOF BY NINE. School Science and Mathematics, 55: 190–198. doi: 10.1111/j.1949-8594.1955.tb16861.x

A simple, rapid method to check multiplication or division, as widely used by the French speaking people, is almost entirely unknown in the United States. Since it is so rapid and simple, the knowledge of this aid deserves wider distribution.

Now, on less literal basis "a prova dos nove" could be one of these alternatives: ... e_id=87085
Henry Cunha 3 18 183
I have to confess that I have never learned, either in Brazil or anywhere else this "proof by nine". My test has always been to reverse the operation, even on a calculator, especially with the use of a memory key, in order to shorten the second input and retain the final value.
PPAULO 6 48 1.1k
It´s simple, at least for addition.

An example:

One would consider 9 as zero. And would add addend by addend, casting out nines at every addition.

At the end compare to the Final Sum (here 23)

If both are equal, then the sum is right.

It would go like this :
5+4=9 same as 5+0=5 (this sum, that is this 5 will be added to the next addend.)

5+3=8 (this sum, that is, eight will be added to the next addend.)

8+6=14 (since it´s >10, the sum of their digits will be also nine-proofed) 1+4+5

Since we know the sum is 23, then nine-proofing it too, it will be 2+3=5

Then bingo! no doubt; the whole operation is right!


It´s a way to know, when one is without a calculator, Excel spreadsheet etc.