Guess My Number

The first personsays, "I'm thinking of a number between 1 and 100. Guess my number." The second person guesses a number. The first person answers, "No, my number is BIGGER than ....(or smaller)". The second person guesses again with the additional clue in mind. Guesses and hints continue until the second person guesses the number correctly.

VARIATIONS:
Younger children can still play with the range of numbers restricted between 1 and 20 as age appropriate.

A harder version is to give math clues than are not "more/less" but are odd, not a multiple of 5, divisible by 3, has no digit 4 in it", etc.