## Welcome to H3 Maths

Blog Support for Growing Mathematicians

## Posts tagged with equations

### How can someone born in 2020 be older than someone born in 2019?

January4

Solution: If someone is born, say, at 1am in the morning of January 1 2020 in Sydney, then everyone born in the UK in the afternoon of December 31 2019 will be younger than them but born the previous year. In fact, the number of people born in 2020 who are older than someone born […]

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### Can you Find the Algebra Exam Error?

November25

In a Level 2 Algebra Exam, held in New Zealand recently, students (and teachers) were flummoxed by some of the questions. Can you spot the error in this one? (Answer in Blog Support shortly)?

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### Find x

December17

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### A Math cartoon for great discussion

April5

This cartoon prompted some really great discussion in my junior math classes…

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### Some Common Math Errors

November6

Errors #1: This image shows a student’s working. What went wrong? Well, obviously x should = 17, not the square root of 17. Perhaps a better way to explain the error is like this: When solving equations (expressions with an equal sign) like this, remember the algebraic rule: “Whatever you do to one side, do […]

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### Math Equations Delay Flight

May8

An Italian maths professor was recently escorted off an American Airlines flight after a fellow passenger feared his mysterious scribbling on a notepad was evidence that he was a terrorist. In fact Guido Menzio was working on an equation connected with a presentation on price-setting he was due to present. He was flying from Philadelphia […]

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### Equations decode the chaos of cancer

January19

A recent news article (in the NZ Herald) indicated some hope in the chase to find effective cancer cures. It noted, “A cancer forms when a cell in the body goes awry, multiplying out of control to form a tumour. A typically-sized cancer tumour is made up of more cells than there are people on […]

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### Talking about Math…let’s change the subject!

May11

So, you are at a friend’s party and they ask, “What did you do in the weekend?” You reply, “Well, I did a bit of Math and…” Whaaat?” they say, startled. “You did What???” “Mathematics!” “And what kind of Math did you do that made your weekend so exciting?” “Change the subject!” you say to […]

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### New Tools to Explain old Newton Equations

May5

One of history’s great geniuses, Isaac Newton (yes, the mathematician with the curly hair sitting under the apple tree), developed differential equations in the 1600s. But we aren’t all geniuses, so here’s the definition given in Differential Equations for Dummies (caution – this link downloads over 300 pages!) such equations “involve derivatives, which specify how […]

### Using Math to predict the future…

October3

Predicting the future to make money – that’s what Ernie Chow does for an investment funds manager. His skill in developing differential equations to model future trends in the stock market, along with his ability to solve those same equations means he can predict the future. Or at least do it as well as science […]

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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)?]