Repunits numbers with all digits = 1.

Automodular number containing its own remainder and divisor.

Power of 2 beginning by given digits.

Prepend prepending a one before a square to get a square

Derviche number The digits rotate by multiplication

Pythagorean perimeter Pythagorean triangles with given perimeter

Pythagorean square Right triangles with integer sides

Gloves Chances to pick a pair of gloves

Handshakes End of party

Resistors Resistors in parallel

Dominoes Count of tiling

Sum of squares Sum of 2, 3, 4 squares, number of decompositions

Divisors Sum of divisors, perfect and amicable numbers

Egyptian fractions The inheritance of camels

Congruent squares 3 squares in arithmetic sequence

The bookseller Equations ax+by=c

The aeronautic meeting A triangular square

The Hasting battle The big army of Harold

The Smith sisters How many sisters in Smith family, and how many socks

The pawns A rectangle or 7 squares

Coin weighings Find one or more fake coins

Fake coins II more fake coins weighings

Bags weighings Find one or more fake coins bags

The fountain Measures by pouring

The thieves Sharing a stolen barrel

Shliced numbers The first k digits build a multiple of k

The explorer Crossing the desert

Two numbers Find 2 numbers, or product of sum and product

Unrelated Shure, a usefull hint !

The ink splash Missing terms in equations

Operations Incomplete operations

Alphametic Operations with letters

Alphametic (2) Operations with letters

Digited numbers Properties of digits in a number

Digited square Properties of digits in a square

Self squared A number equals its square

Self cube A number equal to its own cube

Integer triangles Triangles with integer sides

The Smurfs How many ways of smurfing

The matches Chinese remainder theorem

The clock Angle of hands

The sandclocks Measure of time

The urn Probability of pulling 2 white marbles

Divisors [2] Euler´s totient and square free divisor

Latins Latin and graeco-latin squares