Materials
– A board divided into squares (each 2cm x 2cm) across from left to right and 11 squares from top to bottom. The topmost squares are numbered 1 to 18; from 1 to 10 in red and from 11 to 18 are in blue. There is a red line that divides the board vertically, after the number 10.

– 2 sets of strips; one set is blue with symbols 1 to 9. The other set is red, which are subdivided into squares by blue lines. The end square of each strip is marked with the symbol that corresponds to the number of its squares.