Chris Graham

Chris Graham commented on Probability - Notation and Conversion between Percentages, Decimals and Fractions 8 years, 5 months ago

In the advice, it is not conventional that a comma is placed at the end of the line within a derivation or calculation, as you have with something like

\[\begin{align} x &= \frac{1}{10}\text{,} \\ &= 10\%\text{.} \end{align}\]

An appropriate place to have a comma at the end of a line within the align environment is where you have something more like a list:

\[\begin{align} x_1 &= 2\text{,} \\ x_2 &=4\text{.} \end{align}\]

Sorry, this is probably me brainwashing you about punctuation!

Also, your statement is unrelated to the question content, which is really about conversion. You can keep it in, but should expand on it. 

Chris Graham commented on Finding the highest common factor of two numbers 8 years, 5 months ago

I had 25 marked as prime in part b). I think you may need to update the marking matrix after removing the choice below? 

Chris Graham on Finding the highest common factor of two numbers 8 years, 5 months ago

Gave some feedback: Has some problems

Chris Graham on Decimals to fractions 8 years, 5 months ago

Gave some feedback: Ready to use

Chris Graham commented on Decimals to fractions 8 years, 5 months ago

I fixed the spacing around the = in b)(ii). Otherwise I think this is good.

Chris Graham commented on Using the Quadratic Formula to Solve Equations of the Form $ax^2 +bx+c=0$ 8 years, 5 months ago

I have changed the wording of the statement slightly and also removed "require trailing zeros" in part (a), which was too harsh.

I've removed (i) from part (a) as there is only one sub-part.

Otherwise looks good. However, if this is the first time we meet the quadratic formula (I'm guessing from the way the statement is worded) then I would like to have it available to the student, perhaps as a step to part (a)?

Chris Graham on Using the Quadratic Formula to Solve Equations of the Form $ax^2 +bx+c=0$ 8 years, 5 months ago

Gave some feedback: Has some problems

Chris Graham on Finding the highest common factor of two numbers 8 years, 5 months ago

Gave some feedback: Has some problems

Chris Graham commented on Finding the highest common factor of two numbers 8 years, 5 months ago

I think I would avoid 1 as an option altogether in part (b). Whether 1 is prime or not will trip up a lot of students but is unlikely to be of importance in their studies; I think it's more important to test their knowledge of whether a number is or isn't composite, rather than catch them out on (arguably) a technicality.  

RE your problem in the comment below: h/6 is less than 6 ~50% of the time, so you could either re-think your variables, or use sort to arrange into the correct order, for example set up a new list of numbers containing the factors... sort([1,2,3,h/6,6...]).

There's a mix of singular and plural in the statement. I think I would write "A number that can be...".

"divided evenly by whole numbers" would be better as "divided without remainder..." to avoid confusion with even numbers.

Part (c) in the advice does not provide much additional informtation. I guess you haven't included all of the factors as it would be a pain! That's fine I think. 

Chris Graham commented on Decimals to fractions 8 years, 5 months ago

The student will want to submit each part individually, and for this reason I would split this into two questions.

I have removed the full stops after the fractions. They were not really necessary and their vertical alignment, next to the fraction bar, was awkward.

In (a), clearly (iii) is the toughest. I think I'd swap it for (iv) to give a more logical progression in difficulty.

Where you have \$\displaystyle... you can enclose maths in \[ \] with the same effect.

You also have some centred text in the advice. Note that using\[ \] will centre the maths without the need to centre using the formatting tools.