Category: Math videos

Posted in Algebra, Math videos

Top 10 errors in algebra

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Mathematics is indeed a universal language. Even errors are universal. Here are the top ten errors in algebra which are beyond borders and colors.

#10. Squaring the negative. A minus a squared unless it’s been snared: -8^2\neq 64

#09. Logarithms: The log of the sum ain’t the sum of the log: \log(a+b)\neq\log_a+log_b

#08. Shifting function: Add to y go high, add to x go west: y = (x+3)^2

#07. Inequality: Multiplying the inequality by a negative flips the inequality: -3(x<5) \neq -3x<-15

#06. On exponents: When in doubt, write it out: x^4 = x.x.x.x

#05. Fractional exponent: Don’t flip over the root. 25^{\frac{1}{2}} \neq \frac{1}{25^2}

#04. Subtraction: Don’t forget to share the minus and the negativity. x-(3+x) \neq x-3+x

#03. Cancellation: Cancel factors, not individual terms. \frac {x}{x-5} \neq \frac{1}{-5}

#02. Quadratics: Remember exponents 2, answers 2. x^2=25, x=5, x=-5

#01. Squaring: Don’t forget to FOIL. (x-3)^2 \neq x^2 -9.

Here is a funny video of common algebra mistakes listed above: Continue reading “Top 10 errors in algebra” →

Posted in Math videos, What is mathematics

History of Numbers

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Like all other forms of languages, mathematics developed  because of the necessity to communicate ideas. In the case of numbers, it was to express and record ‘countables’. Below is a little video that can explain this to pupils in the primary grades. Its title is History of Mathematics but I believe it should be titled History of Numbers. There’s no mention of the Greeks and the mathematics they developed.

Our invention of numbers and number system shows us that we are inherently problem solvers ad that we invent symbols and systems to express and communicate our ideas. Mathematics is the most powerful language humans have invented.