Archive for the ‘decimals’ Category


Outdoor Maths Adventures: Middle School

September 16, 2022

As the weather improves – Spring in Melbourne, my city & Fall in USA & Autumn in the UK – it is an ideal time to take math outdoors. Here are some fab exercises for Middle School Math.

Outdoor maths middle school 1 mathspig

Lego Man soccer fields will vary in size depending on the height of each player picked by each student. This does your head in. It is really challenging maths!


Outdoor Maths Middle School 2 Mathspig

McGill Uni link here.

Outdoor Maths MIddle School 3 Mathspig

Don’t forget to throw in Mathspig’s lame protractor jokes.

Outdoor Maths Middle School 4 mathspig

You’ll find full calculations at the Maths is Fun blog.

Outdoor Maths Middle School 5 Mathspig

You’ll find more fab outdoor junior and middle school maths activities at the terrific Maths and Movement blog.

Outdoor Maths Middle school 6 Mathspig

Some students will discover their co-ordinate point is not on the grid. Students should then work out that they will need a different scale for the y-axis. You can get more inspiration at the Stand Again blog.


When Area Calcs mean Big Bucks

August 25, 2022

Bank Notes returned to RBA data.

RBA grids for damaged notes.


NATHAN CHEN wins Gold but Figure Skating Scores can be BAD MATH

February 10, 2022

Nathan Chen, 22, USA, wins GOLD in the Men’s Figure skating with 5 brilliant, soaring quadruple jumps executed to perfection to Elton John’s “Goodbye Yellow Brick Road” and “Rocket Man.”

Nathan Chen’s Winning Performance on You tube HERE.

According to the fab NBC video, Mathletes,  nine Figure Skating judges score competitors for the complexity of each element (eg. Triple axel or triple spin jump) and the quality of the performance producing a score out of ten.

Tessa Virtue and Scott Moir(Above) GOLD Medal performance at Pyeongchang 2018 here.

Kailani Craine, Australia

figure skating score 9 judges nbclearn

This is a typical figure skating score card for one competitor.

The final score, however, is based  on the average for only 5 of these scores. Two are eliminated by random selection (Red Brackets). Then the top and bottom scores are removed and the remaining five scores averaged.

Screen grab NBC Mathletes

Screen grab NBC Mathletes



of Skater A & B:

figure skating score A

Skater A:

Four scores are removed. Two by the random selector (in brackets) and then the top and bottom scores (with line drawn through them)

7.00 + 7.00 + 7.00 + 6.75 + 7.00


=  34.75/ 5 = 6.95

figure skating score B

Skater B:

Four scores are removed. Two by the random selector (in brackets) and then the top and bottom scores (with line drawn through them). But this time the random selector eliminates two low scores.

The average:

7.00 + 7.25 + 7.00 + 7.00 + 7.00


=  35.25/ 5 = 7.05

Same score cards but Skater B gets a higher average score than Skater A.

Skater A is, in fact, beaten by a random number selector!!!!


22 Amazing Numbers for 2022

January 6, 2022

Answers Q 1 – 5 Here

Answers  Q 6 – 10 Here

Answers Q 11 – 16 Here

Answers Q 17 – 22 Here


22 Amazing Numbers for 2022 … Answers Q 6 – 10

January 6, 2022

Ref: Indoor Skydiving

REf: Naomi Osaka

REf: Forbes Mag

REf: Shoe Obsession


22 Amazing Numbers for 2022  … Answers Q 17 – 22

January 6, 2022

Ref: The Guardian, Aus

Ref: New York Times

Ref: (

Ref: Guinness book of Records

Ref: 22 facts about No. 22


Maths in the Real World: 10 Attention Grabbers for Middle School

September 5, 2021

1. Smoke Jumpers: The Amazing Maths of wildfires






2. The Rolling Coin Paradox!!



3. How barcodes work!



4. Pop Song Beats and Jogging


Pop Song Beats and Jogging MATHS HERE


5. Linear Math and Linear Drumming. It’s a thing!


Linear Math and Linear Drumming. HERE


6. Powers and the Loudest Rock Band in the World

Powers and the Loudest Rock Band MATHS HERE


7. Alcohol Kills! Calculate how much would kill you!

Alcohol Kills! MATHS HERE


8. Tall Tales: Is height the most important factor in sport?

Height in Sport maths: USA UNITS HERE

Height in Sport maths: METRIC UNITS HERE


9. Mmmmm! Chocolate. Yes! It can kill  you

Chocolate. Yes! It can kill  you MATHS HERE


10. Random Music? You think!


Random Music?MATHS HERE


The Lego Olympics 2020

July 30, 2021


Death by Chocolate for DOGS

February 22, 2021

choc wrap 1Chocolate can be fatal to dogs. As dogs are small they can easily eat enough chocolate to kill them. According to The Royal Society of Chemistry

Mathspig Death by Chocolate for DOGS

The National Geographic has an amazing interactive chart for dog poisoning by chocolate.


Terrifying Tennis Maths: The Speed of Novak Djokovic’s serve. METRIC

February 7, 2021

USA units post here.

Novak Djokovic is the No. 1 Seed in the Australian Open 2021.

His fastest serve = 219 kph

Could you return his serve? Do the maths!!!!!!

The ball leaves Djokovic’s racket and hits the ground 0.31 secs later.

Go here to see why this simplified calculation works! 

Mathspig tested her reaction time here. TRY IT!

Mathspig’s best, best, best reaction time = O.33 sec

The fastest serve EVER was delivered by Australian Sam Groth @ 263 kph.

That serve takes 0.25 sec to land on the other side of the court.