MathDB

Sergio thinks of a positive integer

S

, less than or equal to

100

. Iván must guess the number that Sergio thought of, using the following procedure: in each step, he chooses two positive integers

A

and

B

less than

100

, and asks Sergio what is the greatest common factor between

A+ S

and

B

. Give a sequence of seven steps that ensures Iván guesses the number

S

that Sergio thought of.
Clarification:In each step, Sergio correctly answers Iván's question.

Problem Statement