Hi, what do you want to do?
Fundación Cientec
Cientec: Juegos Cooperativos
A small collection of 20 or so math brain teasers and word problems, in Spanish. Challenging for younger students -- they use math skills up to multiplication.
University of Cambridge
University of Cambridge: Nrich: Got It
Sharpen your logical thinking and see if you can figure out the strategy to get to the target number before the computer.