Vicky Hall

Vicky Hall on Probability - Notation and Conversion between Percentages, Decimals and Fractions 7 years, 5 months ago

Gave some feedback: Has some problems

Vicky Hall commented on Probability - Notation and Conversion between Percentages, Decimals and Fractions 7 years, 5 months ago

In part a)i), you need to untick the box in the marking section that says 'require trailing zeroes'. I just entered $0.4$ instead of $0.40$ and it marked it wrong. I would put a full stop at the end of all sentences such as 'Convert this probability to a decimal'.

Vicky Hall on Use the quadratic formula to solve an equation in terms of an unknown variable 7 years, 5 months ago

Gave some feedback: Has some problems

Vicky Hall commented on Use the quadratic formula to solve an equation in terms of an unknown variable 7 years, 5 months ago

This is a well conceived question but the answers look a bit nasty! It would be a much nicer question if, when we get to the point of having $\sqrt(xk^2)$, the $x$ is a square number. That way we end up with some quantity of $k$ divided by $2$, which may or may not simplify, but it looks a lot better than having a surd or a decimal. 

Vicky Hall on Using the Quadratic Formula to Solve Equations of the Form $ax^2 +bx+c=0$ 7 years, 5 months ago

Gave some feedback: Has some problems

Vicky Hall commented on Using the Quadratic Formula to Solve Equations of the Form $ax^2 +bx+c=0$ 7 years, 5 months ago

I would give the quadractic formula in the statement and have $x=$ in front of it. I would amend the statement so that it says it can also be useful to use the formula if equations are difficult to factorise (perhaps if coefficients are large), as the equations in part a) and part b)i) could both be solved by factorising instead but using the formula is (probably) quicker. 

The expected answers in part a) are the numbers that would appear in the factorised equation and not the roots so you need to negate the answers and then swap their gaps around.

Vicky Hall on Decimals to fractions 7 years, 5 months ago

Gave some feedback: Has some problems

Vicky Hall commented on Decimals to fractions 7 years, 5 months ago

I think this should be called 'converting decimals to fractions'. Do you have or are you going to make another question on converting fractions to decimals?

The numbers are very large in part b) of the questions. My first fraction was $\displaystyle\frac{681}{10000}$ and my second was $\displaystyle\frac{4365}{999}$. I can see fairly easily that $\displaystyle\frac{681}{10000}$ has no common factor but I had to check with my calculator if $3$ was a factor of $4365$. To fix this, I would reduce the decimal places, so perhaps make the non-recurring decimal $2$ decimal places long, and have the recurring decimal repeat after either $1$ or $2$ decimal places.

Make sure all numbers in the advice are in Latex. In the working for the recurring decimals, it would look much neater to have the $=$ aligned in the subtraction.

I have fixed the notation issue for the recurring decimal in part a).

Vicky Hall commented on Find and use the formula for a geometric sequence 7 years, 5 months ago

It would also be helpful to give and exlain the formula for the $n$th term in the statement.

Vicky Hall on Find and use the formula for a geometric sequence 7 years, 5 months ago

Gave some feedback: Has some problems