Fewer 15-year-olds in East Asian countries reported that they use memorisation than did 15‑year‑olds in some of the English-speaking countries to whom they are often compared. In no PISA-participating education system did boys report more intensive use of memorisation than girls when learning mathematics. Memorisation as a learning strategy may work with easy problems, but it is unlikely to be effective if it is the only strategy used when confronted with complex mathematics problems.