Chris Graham

Chris Graham commented on Using Surds, Rationalising the Denominator 8 years, 6 months ago

Rather than having "Answer:" before the gap, I think I'd rather that the surd was repeated, e.g. "$\frac{1}{\sqrt{11}}=$"

In (g) and (h) your answers are displayed with a decimal on the numerator, which I presume is not what you intended. The reason for this is that the braces evaluate {{n}-sqrt({a})} to a decimal number. Try this instead to retain the integer values of n and a:

({n}-sqrt({a}))/{{n}^2-{a}}.

Good work with the advice, which is well laid out and punctuated.

Chris Graham on Using Surds, Rationalising the Denominator 8 years, 6 months ago

Gave some feedback: Has some problems

Chris Graham on Using BODMAS to evaluate arithmetic expressions 8 years, 6 months ago

Gave some feedback: Has some problems

Chris Graham on Algebra vocabulary 8 years, 6 months ago

Gave some feedback: Has some problems

Chris Graham commented on Algebra vocabulary 8 years, 6 months ago

This question is crying out for a different part type, or rather a variant on match choices with answers. I'll have a think about that...

As it stands I find some of the definitions a little confusing. E.g. "Tell me what... equals. i.e 5x = 30 therefore x=6" is very difficult to read as a sentance. Think dictionary entries with a mathematical twist: "To obtain the solution to a mathematical problem. For example, given $5x = 30$, to find that $x=6$.

You should use LaTeX for mathematical expressions, even in the definitions. I think for the sake of completeness, including all of the definitions again in the advice would give the student something that they could write down / copy / reference.

Chris Graham commented on Using BODMAS to evaluate arithmetic expressions 8 years, 6 months ago

The statement begins "Apply BODMAS..." What if the student has never seen this acronym. I think I would begin with a short summary, or at least add this as a step, so that they can seek help. 

You don't need the horizontal lines in the advice. There;s nothing particularly wrong with them aesthetically, however they're inconsistent with other questions.

Try to punctuate equations in the advice as discussed yesterday.

Chris Graham commented on Expand brackets and collect like terms 8 years, 6 months ago

I've changed the Doesn't Work status as it seems to run OK. What was the problem?

The statement is currently more of a description of the question, rather than instructions for the student. "For each of the expressions below, collect terms..." would be more direct.

In part b) you can use the string restrictions tab to set the expected variables and warn the student if they use anything other than those.

The prompt in b) starts quite abruptly with "One bag...". Why not say e.g. "Brad has two bags of tokens. The first bag contains..." I think I would move the bag contents to two lists, which is easier for the student to work with.

In the advice you have some small errors e.g. $7z(=$, and you could make use of the align environment. Similarly with part (b).

In the final part of the advice I would give an expression for each bag first, in terms of $r,b,y$ and then put the two together.

Chris Graham on Expand brackets and collect like terms 8 years, 6 months ago

Gave some feedback: Has some problems

Chris Graham commented on Factorising Quadratic Equations with $x^2$ Coefficients Greater than 1 8 years, 6 months ago

In part a), i),ii) should be in italics, and I would start a new line afterwards.

You need some string restrictions in part (a), for example I can enter the expression into the gap as given, and get full marks. See the bottom of the Numbas tutorial.

In (b) and (c) "values of x in the following equation" would be better expressed as "values of x which satisfy the following equation".

In the advice, put a),b)... on a new line, and preferably set the style using format->Formats->Headings->Heading 4

The advice is not easy to scan, and unfortunately students will not take care to read the whole thing. Help them out by placing any important equations on a new line, so that the student can easily see how the solution develops. And as a general rule, use display style for any equations on their own line.

In part (d) of the advice you obtain the possible values of x, however this is not asked in the question. Did you intend to include this? If you do so you will need to think about the precision that you would like, and formatting in the advice (see e.g. dpformat on the jme reference page).

Chris Graham on Basic arithmetic operations: addition and subtraction 8 years, 6 months ago

Gave some feedback: Has some problems