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Number 5: Do you know what an automorphic number is?

It's been an inspirational May (the 5th month!), packed full of schoolkids, boybands and acts of kindness

Last week I was thrilled to run a maths incursion for the lovely students at Bronte Public School in Sydney. Our wild numerical ride involved factors, prime numbers, and calculating the powers of two up to a number so massive I literally saw kids' jaws drop. If you’re keen to know what the students and I worked on, it was material very similar to my 2013 TED Talk on massive prime numbers (the size of the world’s largest known prime has increased significantly since then!) A big thanks to Jack Singleton and the teachers and students of Bronte PS - including Luca McCarthy, Hugh Graczer, Bill Singleton and Tom Singer who are pictured above (L-R) with me. I hope you enjoyed the day and rip into those copies of my books!

Are you ready to be blown away by the automorphic beauty of 5?​

5 x 5 (or 52) = 25, which ends in a 5. Multiply this again by five: 5 x 5 x 5 (or 53) = 125, which again ends in a 5. Keep on multiplying by five: 54 = 625; 55 = 3125; 56 = 15625 and so on, and the answers all end in a 5. If you think about it, no matter how many 5s you multiply together, the last digit of the answer will always be a 5! So we call 5 an ‘automorphic’ number, meaning ‘patterned after self’, because it keeps repeating itself at the end of these multiplications. Read more about automorphic numbers further below ㋡

Enjoy these fascinating numerical facts about 5!

Child prodigy Learning to play piano at age 3, Mozart wrote his first composition by age 5! check out 'A Minuet and Trio in G Major' to feel both inspired and inadequate

Basic elements​ In Hinduism, the natural universe comprises five basic elements – earth (pritvi), water (jala), fire (agni), air (vayu) and ether (akasha).

Chanel No. 5 In 1921, French designer Coco Chanel paid homage to her favourite number five by releasing her perfume Chanel No. 5 on the fifth day of the fifth month – 5 May!

INSPIRATIONAL THINKERS & DOERS - Kath Koschel, Four million acts of kindness​

As the father of two daughters (and now a stepdaughter thrown into the deal!), I think often about diversity and the opportunities afforded to young women and girls. While hosting the Victorian Primary School Principals conference, I met the amazing Kath Koschel who is a former elite cricketer and founder of the Kindness Factory. Kath challenges people to connect with others through acts of kindness, focusing on mental health and resilience. Since 2015, almost 4 million acts of kindness have been performed and logged via her initiative! A case study in resilience herself, Kath has faced multiple setbacks in her life – including two broken backs – but she’s refused to let this stop her success. Kindness Factory initiatives run in over 200 schools and can also be one-off gestures. Kath's work also supports research into the benefits of kindness – social, psychological, neurological and more. Why don’t you, your workplace or your child’s school commit to acts of kindness today? Go to to learn more.

Automorphic numbers continued

Automorphic numbers aren't just single digits. Check out 25. Repeated multiplication by 25 gives 625, 15625, 390625 and so on, all ending in 25. In fact, there is an infinite number of automorphic numbers! If you’re feeling excited by this - or have a rapacious child who hungers for maths problems - have a crack at this… The first few automorphic numbers are 0, 1, 5, 6, 25, 76, 376, 625, 9376, 90625, 109376, 890625 and 2890625. Now prove it! Good luck and I’ll see you in a few hours ㋡

5ive touring Australia

My good friend Charlie Clausen would never forgive me for not sharing that iconic Brit boy band 5 (sometimes written as 5ive) are touring Australia in November. And when I say 5, I mean ‘the remaining 3 of the original 5 members’ – unfortunately for fans of Abz Love and Jason ‘J’ Brown, only Sean, Ritchie and Scott are coming Down Under. Charlie has a very funny podcast TOFOP with my old radio buddy Wil Anderson. Tune into recent episodes covering his bizarre fascination with this tight-dancing, hard-rapping quintet established as a wannabe male version of the Spice Girls. So, if you used to shake your booty to 'Keep On Movin’ and 'When the Lights Go Out', get along to your nearest venue and convince yourself it's 1999 all over again. Buy tix Yours in numbers, Adam


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