Magic: Guess numbers via mobile phone

This is it... C and B are colluding. For example, if A guesses the number 64, then B calls C. After receiving the call, he starts counting 1, 2, 3, 4, 5. 6 When counting to 6, B says "Hey!" 》C will know that the tens digit of this number is 6. Then continue to count 1, 2, 3, 4 to 4. Then I will say "Hello" and then know that it is 64. Then B will say that the phone is connected. I will give the phone to you yourself. Just ask him if he's okay. I don't know if I explained it clearly enough... Liu Qian's book Magic Visa contains this magic called telepathy