## Welcome to H3 Maths

Blog Support for Growing Mathematicians

## Archive for May, 2013

### How a math formula helped win WWII

May30

“Here is a story (from The Guardian, 2006) about mathematical deduction … that had an impact … on the outcome of the second world war. It is the story of how a simple statistical formula successfully estimated the number of tanks the enemy was producing, at a time when this could not be directly observed […]

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### Fractions the Wacky Way

May29

Students often struggle with combining different fractions. This technique is a good quick way to learn how to add, subtract, multiply and divide fractions and it certainly helped my students work out some quite complex fractions: There are many other “Wacky” ways of doing Maths (but I would not recommend them all) which may help […]

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### Exponential Growth – Pt II. Powers of 2

May28

The bottom graph shows a linear (straight line) graph -where the numbers are increasing at the same rate? Actually, if you look closely at the y-axis you will notice that the scale is not in even steps. It uses a log scale (or powers of ten).  If the scale is changed to even steps then […]

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### Exponential Growth – the fish grow crazy

May27

If a population has a constant birth rate through time and is never limited by food or disease, it has what is known as exponential growth. With exponential growth the birth rate alone controls how fast (or slow) the population grows. Click this applet to see the effect:

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### Get the Math

May22
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### Autism and the love of equations…

May20

“I am sitting at the back of a university physics class while the students cluster in small groups around the whiteboards…ready to tackle the day’s equation… I see my nine-year-old son at the front of the room, chatting easily with the professor. Finally, my son pulls a chair over to a whiteboard and steps up on […]

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### Mirror, mirror on the wall…who is the greatest mathematician of all?

May19

Now that is a loaded question! After all, how do you compare such great minds? For example, Euler was perhaps the most published mathematician with about 900 books to his name. His most famous formula, eiπ + 1 = 0 where e is the mathematical constant and i is the square root of minus one, is considered by many to […]

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### Pi from Pies…

May18
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### Multiply up to 20 x 20 mentally!

May18

In just FIVE minutes you can learn to quickly multiply up to 20×20 in your head.  With this trick, you will be able to multiply any two numbers from 11 to 19 in your head quickly, without the use of a calculator (assuming that you know your multiplication table reasonably well up to 10×10). Example: […]

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### If maths is boring, what is the answer?

May17

Marcus du Sautoy, Professor of Mathematics at Wadham College, Oxford notes, “Who said maths was boring? A report published by Ofsted last month claimed that pupils are simply turned off by the parrot learning of formulas to solve quadratic equations and the mindless application of the rules of trigonometry. An obsession with teaching children solely […]

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#### Post Support

The graph on the left (Coronavirus) is for a time period of 30 days, while the one on the right (SARS) is for 8 months! Very poor graphical comparison and hardly relevant, unless it is attempting to downplay the seriousness of the coronavirus?

10 x 9 x 8 + (7 + 6) x 5 x 4 x (3 + 2) x 1 = 2020

NCEA Level 2 Algebra Problem. Using the information given, the shaded area = 9, that is:
y(y-8) = 9 –> y.y – 8y – 9 =0
–> (y-9)(y+1) = 0, therefore y = 9 (can’t have a distance of – 1 for the other solution for y)
Using the top and bottom of the rectangle,
x = (y-8)(y+2) = (9-8)(9+2) = 11
but, the left side = (x-4) = 11-4 = 7, but rhs = y+? = 9+?, which is greater than the value of the opp. side??
[I think that the left had side was a mistake and should have read (x+4)?]