Thursday, 7 July 2016

The Anti Primes

During the winter break I saw a video on Numberphile about Antiprimes. This was very exciting for me because I didn't realise it was a real term. Turns out it isn't, they have another cool name for numbers that have lots of factors but one of the Numberphile crew also likes the term Antiprime and that's good enough for me (:

And they confirmed that 360 is one of these numbers.

The 8 Times Tables Can Be Cool

As many of my students know I do not enjoy times tables. I missed quite a bit of primary school maths so speedy tables are not my thing. In particular it's the 8s that make me pause the most. Speed doesn't matter, it's the process. For me it's just doubling my four times tables.

Bec Campbell shared the following with me and yes it is pretty cool. Even cooler is to ask why it happens....

Thursday, 9 June 2016

Thanks to Aidan and 7D for sharing this funny mathematics from Abbot and Costello

Check out "Who's on First?", also by them. It's one of my favourites.

Wednesday, 1 June 2016

It's been a while, babies and blue whales

Year 7 has been very busy in term two doing things like school camps and NAPLAN. 
Now we are back with our full weeks of math and looking at patterns in the real world. 

Today we looked at the growth rate of babies in their first 13 weeks. 

The WHO provides the data - we used every two weeks to develop models for predicting - interpolating and extrapolating. This way we could check our maths with the real data! 

We used tables, graphs and developing algebraic rules to make predictions and compared their results.  Alex pointed out how ridiculous it would be to keep using our models into teenage years to illustrate how extrapolation can be unreliable.  Here are some notes from today and Alex's example:

How reliable are our models?
Reasonably reliable for interpolating. 
Not as reliable for extrapolating. Remember Alex calculated the weight of a 13 year old at the same growth rate as babies in their first 13 weeks. 

13 years = 13 x 52 weeks

13 years = 676 weeks

Our formula/equation/rule

Let  t = time weeks   and   k = weight in kg
k = 0.25 x t + 3.3
for 13 years old
k = 0.25 x 676 + 3.3

k = 172.3 kg 

That's not average in any country for a 13 year old boy!
The CDC, in the USA,  says the average weight for a male at 13 years old is 51.68229 kg  That's more than 100 kg lighter than our formula says. 
Can you find the average weight of a 13 year old in another country?


We talked about including units on our work to show kilograms otherwise our baby data could be in tonnes or even milligrams. A 3 tonne baby! Crazy!
... or not....? I did some searching....

For interest: Close to 3 tonnes are baby blue whales and their average difference is about 91 kg a day!!
Their formula would be k = 91 x d + 3000 and reliable for 365 days! 
where k = weight in kilograms and d = time in days. 3000 is the initial value (or 2700 - see below). 
After about a year inside its mother's womb, a baby blue whale emerges weighing up to 3 tons (2.7 metric tons) and stretching to 25 feet (8 meters). It gorges on nothing but mother's milk and gains about 200 pounds(91 kilograms) every day for its first year.

Blue Whales, Blue Whale Pictures, Blue Whale Facts - National ...

Tuesday, 19 April 2016

Scientists need you to count cute baby penguins via the Washington Post

During my morning commute I read about a great project involving penguins, counting, science, ecology and collaboration. That's a lot of boxes ticked.

You can provide some community service by counting penguins in images supplied by scientists.

I was fortunate enough to visit Antarctica in 2013 and loved the penguins. I'll be counting penguins for science and our world. I hope you do too.

You can read the Washington Post article via this link.
You can check out the project via this link.

Please enjoy two of my favourite penguin photos (I have hundreds)!

Antarctica Wildlife

Not all penguin tummies are white. This one is fine, just a messy eater. That's his lunch you can see. 

Saturday, 9 April 2016

Base 64 and Youtube

We use base 10 and computers use base 2, aka binary. There are all sorts of number systems and here is another one to think about and it's how Youtube doesn't run out of short urls.

Tuesday, 5 April 2016

Cool Maths Facts

Check out these slides of interesting maths facts.
I think the Monster Prime might be out of date now...


 I like this site because they cite their source on each page. That's principled!