Vicky Hall

Vicky Hall commented on Calculate a student discount 7 years, 5 months ago

Parts b) and d) are testing subtraction rather than percentages so remove these parts. If you wanted to bulk out questions you could combine the ideas in parts a), c) and d) into a single question. Some questions giving the new price after the percentage change and asking students to calculate the old price would be good here to demonstrate that it matters which number you take the percentage of (this often confuses students). It would also be a good idea to have students calculate the percentage change bewteen two prices.

In the advice, I would include mulipliers as one of your possible methods for calculating percentages. For example, to find $25%$ we can mulitply by $0.25$. To increase something by $10%$, we can multiply by $1.1$.

Vicky Hall on Rounding numbers to a given number of significant figures 7 years, 5 months ago

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Vicky Hall commented on Rounding numbers to a given number of significant figures 7 years, 5 months ago

In the advice you say '295 rounded to the nearest ten is 300 and NOT 2100'. I don't think this is a common mistake! I would remove this line and instead explain that sometimes the nearest ten is also the nearest hundred. You should add an extra question at the very start where the nearest ten is not also the nearest hundred. 

When adding subparts to questions, you don't need a full stop and a parenthesis. Just use the parenthesis.

Vicky Hall on Inverse and composite functions 7 years, 5 months ago

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Vicky Hall commented on Inverse and composite functions 7 years, 5 months ago

The expected answers are not simplifed here. For example, I entered $\displaystyle \frac{x+6}{10}$ (which was marked as correct) but the expected answer displayed as $\displaystyle \frac{\frac{x-2}{2}+4}{5}$. This is the same in the advice, except here the answer displays as $\displaystyle ((x-2)/2+4)/5$, which is a nightmare to read! Have the advice display the solution in its simplest form and use \frac.

Vicky Hall commented on Fraction multiplication 7 years, 5 months ago

I would change the staement to say something like 'evaluate the following multiplications, giving each fraction in its simplest form'.

In part b), the expected answer is incorrect. When I tried it, the fraction in its lowest terms was $\displaystyle\frac{81}{104}$ but the expected answer said $\displaystyle\frac{162}{208}$. The correct answer appears in the advice though.

In part c) the fractions $\displaystyle\frac{3}{7}$ and $\displaystyle\frac{1}{3}$ should be variables. I know you've picked these numbers so that the answer always comes out as a whole number of days, which of course it must, but it would be much better to get Numbas to produce the variables so that the sum will always work out nicely, otherwise students can only do the question once. Also, display these fractions using \frac.

In the advice, you tend to use colons before stating a result. For example, '...final answer is: $\displaystyle\frac{81}{104}$'. You don't need the colon here, just give the number.

Vicky Hall on Fraction multiplication 7 years, 5 months ago

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Vicky Hall on Use formulae for the area and volume of geometric shapes 7 years, 5 months ago

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Vicky Hall commented on Use formulae for the area and volume of geometric shapes 7 years, 5 months ago

I meant to link all formulae to the question so that the student understands why they have been given a particular formula. When asking them to calculate the volume of a tennis ball, tell them that you are providing the formula for the volume of a sphere. Hopefully this will help them to learn the correct formulae at the same time as practising substition.

Ensure that in all formulae the words 'Area' and 'Volume' are in Roman and also use \displaystyle to make the formulae clearer. Use $\sin C$ instead of $sin(C)$. 

It's not necessary to state the value of $\pi$ (and certainly not after every part of the question!) as the student will be using their calculator for these questions anyway. 

Please remember full stops at the end of all sentences.

Most of these comments also apply to 'Substitutuion without geometry' as well so please have a check through that too.

Vicky Hall on Use formulae for the area and volume of geometric shapes 7 years, 5 months ago

Gave some feedback: Has some problems