As part of an NCETM project, the author is involved with three local schools investigating how engaging in role play might aid children's mathematical development. The project embraces children ranging from part-time Reception to Y4. In this extract, two Reception-age girls, Rachel and Connie, are playing in their classroom spacecraft, and need a short length of wool to be used as strap. The author shares the realizations she had while observing the two girls in their play. She shares that after witnessing the scene in Rachel's class, she immediately saw a teaching opportunity to look at how numbers are used on tape measures.