Ask a friend to write down a number of three or more digits,divide by 9,
and tell you the remainder.
Then ask him cross out any digit except 0, divide the remaining number by 9, and tell you the remainder.
At once you name the digit crossed out.
The method.
If the second remainder is smaller than the first, subtract from the first.
If the remainders are equal,the crossed out digit is 9.
Explain.
Ask a friend to write down a long number, and then write a second number composed of the same digits.
です。
できたら訳もお願いします。