Transition to university

Christian Lawson-Perfect on Lowest common multiples: train timetable example 8 years, 5 months ago

Saved a checkpoint:

Part a is a bit too simple for an incoming university student. 

This question should focus just on calculating least common multiples. Remove part a, leaving the nice wordy question. You could have another very simple separate question asking to find the LCM of two numbers when:

• they're coprime;
• their GCD is bigger than 1 but not equal to either number;
• one is a multiple of the other.

I think it should be "platform A" instead of "track A".

I got periods of 12 and 6 minutes for the two platforms - could you make sure that the LCM isn't either of the given numbers?

Chris Graham on Addition and subtraction of fractions 8 years, 5 months ago

Gave some feedback: Ready to use

Chris Graham commented on Addition and subtraction of fractions 8 years, 5 months ago

I've made some very minor changes to the advice. Looks good now.

Christian Lawson-Perfect on Calculate a student discount 8 years, 5 months ago

Gave some feedback: Has some problems

Christian Lawson-Perfect on Calculate a student discount 8 years, 5 months ago

Saved a checkpoint:

I don't think anyone in the history of shopping has had a voucher for a 12% discount. Pick multiples of 5%.

The line in the advice about not rounding until the end is incorrect - in this instance you can round off the discount before subtracting it from the original price. If you were subtracting two discounts, or performing a further calculation with the discounted price, you might encounter problems. 

"This does not make sense in the real world" needs to be more precise - something like "The shop would round this discount to the nearest penny" would do.

I don't think I agree with "Method 1 is a bit simpler and more appropriate to use." - simplicity is in the eye of the beholder! Just briefly describe each method instead: "the first method involves working out the discounted price as a percentage of the original, while the second method calculates the value of the discount and subtracts that from the listed price."

Christian Lawson-Perfect on Use the quadratic formula to solve an equation in terms of an unknown variable 8 years, 5 months ago

Gave some feedback: Has some problems

Christian Lawson-Perfect on Use the quadratic formula to solve an equation in terms of an unknown variable 8 years, 5 months ago

Saved a checkpoint:

The marking is set up wrong: $k(-6)$ is the application of the function $k$, not $-6 \times k$. You can avoid this by writing $(\ldots)k$ instead of $k(\ldots)$.

It's not obvious what order you should enter the roots. The best I can come up with for a hint is "Assuming $k$ is positive, enter the lowest root first." I can't think how to be any clearer without giving a hint about the form of the answer.

You need \left and \right around brackets to make sure they stretch to fit around fractions.

Put the quadratic formula in the advice just before you list the values for $a$, $b$ and $c$.

Chris Graham on Use the quadratic formula to solve an equation in terms of an unknown variable 8 years, 5 months ago

Gave some feedback: Has some problems

Chris Graham commented on Use the quadratic formula to solve an equation in terms of an unknown variable 8 years, 5 months ago

When the variable C_2 is zero, your advice states $c = 0k^2$, which caused me great confusion (about where the $k^2$ had come from) when I was unlucky enough to generate this on my first attempt. If you would like to keep this scenario, then you will need to adjust the advice, or if it is not desirable then use an except in the generation of B_2 or n2. 

Chris Graham commented on Find the equation of a line through two points - negative gradient 8 years, 5 months ago

Good work with the adaptive axis ranges, however in some cases the x axis is objectionably at edge of the board, as the maximum of the y range evaluates to 0. Use the javascript function Math.max() to set a minimum range displayed above the axis, e.g. Math.max(yb+4,2) would set the 'y-max' to a minimum of 2.

You could use a similar method to check that the intercept is on the board (it currently isn't always).

Check your spelling, e.g. "coordiantes" and that your sentences read fluidly, e.g. "find the straight line equation of the line running through these points" can be written "find the equation of the straight line running through these points" and so on.

Chris Graham on Find the equation of a line through two points - negative gradient 8 years, 5 months ago

Gave some feedback: Has some problems

Christian Lawson-Perfect on Calculate the measures of central tendency for a sample 8 years, 5 months ago

Gave some feedback: Ready to use

Christian Lawson-Perfect on Calculate the measures of central tendency for a sample 8 years, 5 months ago

Saved a checkpoint:

A good simple question.

Here's a simpler way of making sure you've got a unique mode: generate a random set of 19 values. Find a modal value of that set (there might be more than one), and add another instance of that value to get a list of 20 items with a unique mode.

Stanislav Duris on Cumulative percent decrease 8 years, 5 months ago

Gave some feedback: Has some problems

Chris Graham on Completing the square 8 years, 5 months ago

Gave some feedback: Has some problems

Chris Graham commented on Completing the square 8 years, 5 months ago

You seem to have sorted the pattern matching and there is a nice gradient of difficulty now.

In the part prompts, replacing e.g. "the expression" with "the following expression" will be clearer to the student.

I would suggest that part (d) becomes its own question, and then you could split this into two parts: the first part completing the square and the second finding the solutions.

Aiden McCall on Calculate the areas of polygons 8 years, 5 months ago

Gave some feedback: Has some problems

Aiden McCall on Calculate the areas of polygons 8 years, 5 months ago

Gave some feedback: Doesn't work

Aiden McCall on Use formulae for the area and volume of geometric shapes 8 years, 5 months ago

Gave some feedback: Doesn't work