A maths blog for teachers / anyone with an interest in mathematics — with posts about maths and its awe-inspiring stories, resources and problems free to download, and collections of links to the most fascinating maths audio and video out there: mathsedideas.blogspot.com

For the 104th day, the 13th day of the 4th month of the 2024th year:

104 =
(13 − 4 × √(2 + 0 − 2 + 4)) ×
(13 − 4 × √(2 + 0 − 2 + 4)) ×
(13 − 4 × √(2 + 0 − 2 + 4)) −
13 − 4 × √(2 + 0 − 2 + 4)

Ask ChatGPT to pick a number between 1 and 100 - which does it pick?
(by Leniolabs_)

In 1991 a list of large semiprimes were generated on a computer whose hard drive was destroyed to remove any record of the prime factors.

In 2020 the 250-digit semiprime (RSA-250) became the largest encryption key ever factored, using 2700 CPU-years: bit.ly/3xwHrwX

What percentage of the whole square is the hole?

Sequentially stringing together all the numbers from 1 to 10 and then back down to 1 gives the first ‘memorable prime’:

12345678910987654321

The next is probably the ‘gigantic’ 17350-digit:

12345678910111213…244524462445…13121110987654321

But we know of no others.

Random Acts of Maths — over 300 pocket-sized problems, teasers, curios, provocations, inspirations, etc., for teachers to gift to students, school visitors, et al. Free to download, with solutions and slides: bit.ly/2MkTnFM • #math s #math #MTBos #iteachmath

Indian mathematician Brahmagupta imagined a number for nothing (śūnya शून्या in Sanskrit, ‘vacant’) in 628 CE → The idea reached the Middle East via al-Khwārizmī (ʂifr صِفر in Arabic, ‘cipher’) in 825 CE → It spread through Europe via Fibonacci (‘zero’ in Italian) in 1202.

In recently showing that the Collatz conjecture now holds for all numbers up to

1,770,887,431,076,116,955,136

David Bařina's computing systems checked around 220 billion numbers per second, or just over 7 numbers per 1cm of light travelled! bit.ly/3W1vTMv

‘The most fantastic magic square ever discovered’, in the words of Martin Gardner. Lee Sallows’ Alphamagic square: A magic square that remains magic when its numbers are replaced by the number of letters in the name of each number. bit.ly/2DfXIrX

A catalogue of links to >150 mathsy videos and clips — arranged by theme — for teaching hooks, curriculum enrichment, or just to dip into, relax, share, and enjoy. Including from Vsauce Veritasium Grant Sanderson Royal Institution Oxford Mathematics and more: bit.ly/3IUiWwb

Two vertices of a square lie at the centre and a vertex of a regular hexagon. What fraction of the square lies outside the hexagon?

For a solutions ‘think through’ and slides to use in the classroom: bit.ly/4anPKZY

For the 81st day of the year, an 81 digit prime number:

111,111,111,111,111,111,111,111,111,111,111,111,111,161,111,111,111,111,111,111,111,111,111,111,111,111,111

Or to put it another way…

A set of 100 mathematical quotes, curios, provocations, etc., to colour our corridors with mathematics. For free downloads including an editable versions: bit.ly/499EPlv