Christian Lawson-Perfect

Christian Lawson-Perfect on Using BODMAS to evaluate arithmetic expressions 8 years, 6 months ago

Gave some feedback: Ready to use

Christian Lawson-Perfect on Using BODMAS to evaluate arithmetic expressions 8 years, 6 months ago

Saved a checkpoint:

This looks good! I changed a few words to sound more natural in English.

Christian Lawson-Perfect on Using the Logarithm Equivalence $\log_ba=c \Longleftrightarrow a=b^c$ 8 years, 6 months ago

Gave some feedback: Has some problems

Christian Lawson-Perfect commented on Using the Logarithm Equivalence $\log_ba=c \Longleftrightarrow a=b^c$ 8 years, 6 months ago

Do each of the subparts assess different things? If not, you might as well just have one of each - the student can click "try another question" if they want more.

The advice for part c doesn't show how to enter the answer. Students can't type $\sqrt[4]{x}$, so you need to say something like, "enter this as x^(1/4)", or add a line "$ = x^{1/4}$" to the end of the working-out.

I'm not keen on the sudden appearance of $n$ in the advice for part d! I think you're just shuffling things around to show what you've already been given. The expressions you have to resolve are all just stock identities, so I don't think there's anything to explain.

Christian Lawson-Perfect on Quadrant coordinates MCQ 8 years, 6 months ago

Gave some feedback: Has some problems

Christian Lawson-Perfect commented on Quadrant coordinates MCQ 8 years, 6 months ago

Name the quadrants A,B,C,D instead of 1,2,3,4. Or could you give them compass coordinate NW,NE,SW,SE? Trying to keep two coordinate numbers in your head and then remember a number for the corresponding quadrant will tax some minds! It sounds silly but difficulty with holding numbers in your head is much more common than you'd think.

It looks like part a is always in the top-right quadrant, and similar for the next three parts. If you replace parts a to d with a "match choices with answers" part, you can shuffle the order of the choices, so that the answer isn't the same every time.

You could do the same with parts e to g.

The explanation at the top of the advice is very wordy and hard to follow. Here's my version:

You can think of a pair of coordinates as a directions to the desired point, starting from the origin.

The first part of the coordinates tells you how far to move along the horizontal $x$-axis. Positive numbers are on the right and negative numbers are on the left.

The second part of the coordinates tells you how far to move along the vertical $y$-axis. Positive numbers are above the origin and negative numbers are below.

For each part, something like "the first part is positive and the second part is negative, so the point lies in quadrant 3".

Lots of spelling mistakes - "coordiante", "axsis".

"All points on the x-axis correspond to a y value of 0, so we can assume that anything on the line y=0 is on the x-axis." is a little bit wrong. We don't assume anything. By definition, points with zero $y$ coordinate are on the $y$ axis.

For $(0,0)$ - your explanation is very long-winded. You can just say "the $x$ coordinate is 0 so it's on the $x$-axis, and the $y$ coordinate is zero so it's also on the $y$ axis."

Check the order of the parts in the advice.

Christian Lawson-Perfect on Fraction multiplication 8 years, 6 months ago

Gave some feedback: Has some problems

Christian Lawson-Perfect commented on Fraction multiplication 8 years, 6 months ago

This looks good, but part d seems vindictively hard! What's it assessing?

From the advice, it looks like:

• BODMAS - this isn't what the question's about
• Squaring fractions - have a smaller question on this earlier, e.g. "calculate $\left(\frac{a}{b}\right)^2$".
• Division of fractions - again, not what the question's about.

I reckon you could just delete part d, or spin it into a separate question.

Christian Lawson-Perfect on Solving linear inequalities 8 years, 6 months ago

Gave some feedback: Has some problems

Christian Lawson-Perfect commented on Solving linear inequalities 8 years, 6 months ago

Parts

Part e has "x<..." in the expected answer. It should just be a number.

In part f, I think you've forgotten the coefficient of $a$.

Advice

I've corrected "on it's own" to "on its own".

Why were there sometimes brackets around the numbers? I've removed them.

Part d: minus signs have gone missing in the second line. You say you've highlighted something in red, but I can't see it because I'm colourblind. Find a way to refer to things in text.

Something's gone wrong in part e: the right-hand $x$ term goes missing in the second line. And I wouldn't think of this as pulling out a factor of $x$ anyway: you're collecting like terms. The thrid line seems to be nonsense too.

Part f: I think the second line is supposed to have collected all the $x$ terms on the left, but the coefficient is wrong. And then I got a third line showing division by $15-5$. Why wouldn't you collect together first and just divide by $10$?

I dispute that it's easier to divide first in part $g$! I got an $h$ term and the advice says to divide by $2$ first. Maybe make sure that you're dividing by the gcd of all the coefficients, and the gcd is greater than 1.