MATHS WEEK STARTS today and, as is our annual tradition, we’re setting our readers some puzzles. Give them a go!

Maths is very important in life and we’re are often using it without realising.

Unfortunately, many people have a bad experience learning maths and it is very difficult to learn a subject if you have a negative attitude towards it.

That is why Maths Week Ireland seeks to promote a positive attitude for all with fun and challenging activities.

Our brains are well evolved to have a good intuition for addition and we even have a good feel for how numbers will multiply. However, when it comes to percentages our intuition often lets us down.

Things like loan repayments and compound interest are not at all obvious to us and if
not well informed, we can make very poor financial decisions.

See how you get on with the following more straightforward, but interesting questions, with maybe surprising answers.

A. Your boss agrees to give you a 10% pay rise. A year later, she changes her mind and says she will have to reduce your pay 10%. “Oh well,” you think to yourself, “At least I’m back to where I started.” Are you?

B. Your brother’s boss agrees to give him a 25% pay rise. A year later, he changes his mind and says he will have to reduce your brother’s pay 20%. “Oh well,” your brother
reasons, “At least I got a 5% raise overall.” Did he?

C. Your sister’s boss agrees to give her a 20% pay rise. A year later, he changes his mind
and says he will have to reduce your sister’s pay 15%. “Oh well,” your sister reasons, “At
least I got a 5% raise overall.” Did she?

D. Your friend’s boss agrees to give her a 25% pay rise. A year later, he changes his mind
and says he will have to reduce your friend’s pay 24%. “Oh well,” your friend thinks to
herself, “At least I got a 1% raise overall.” Did she?

E. BONUS: Your pay is slashed 20% five years in a row. What is the overall pay cut? Is it
100%? Do you end up earning anything at all?

Come back tomorrow, same time, for the answers.

Maths Week Ireland is coordinated by SETU with partners across the island of Ireland. This year over 400,000, north and south will take part and these puzzles give you a chance to participate. The Maths Week puzzles this year are presented by Colm Mulcahy, professor emeritus of Mathematics at Spelman College, USA, and adjunct professor with Calmast at South East Technological University. Colm is chairperson of the Martin Gardner Foundation USA, and the curator of the website mathsireland.ie