Copyright © University of Cambridge. All rights reserved.

See all short problems arranged by curriculum topic in the short problems collection

A knitted scarf uses three balls of wool. I start the day with $b$ balls of wool and knit $s$ scarves. How many balls of wool do I have at the end of the day?

If you liked this problem, here is an NRICH task which challenges you to use similar mathematical ideas.

*This problem is taken from the UKMT Mathematical Challenges.*