Lauren Richards- Numbas at mathcentre.ac.uk

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Lauren Richards commented on Decimals to fractions 7 years, 4 months ago

Everything is fixed now EXCEPT part b)i) STILL does not simplify properly for some unknown reason. It gave 342/1000 as that instead of 171/500 and another time 302/1000 instead of 151/500 and again another time 416/1000 instead of 52/125.

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Lauren Richards on Decimals to fractions 7 years, 4 months ago

Gave some feedback: Has some problems

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Lauren Richards on Lowest common multiples: train timetable example 7 years, 4 months ago

Gave some feedback: Needs to be tested

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Lauren Richards created Lowest common multiples: train timetable example 7 years, 4 months ago

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Lauren Richards commented on Decimals to fractions 7 years, 4 months ago

Explanation for "Doesn't work":

The problems with this question are in part b) - part a) is mostly fine.

In part a), I am slightly unhappy about it the apparent impossibility of aligning whilst having an underline. I have a subtraction in part a) and wanted the answer to the subtraction directly underneath the subtraction with an underline separating it but I couldn't get it to work so I now have it not underlined and separated but still aligned.

The big problems are in both sections of part b).

b)i) - The unsimplified fraction does not simplify properly using either gcd or the \simplify command and I cannot for the life of me work out why not. Vicky previously thought the problem was that the numerator and denominator of the fraction were not variables but I have made them so and it still will not 1) identify the correct gcd nor 2) simplify properly. For instance, on the last run it said that with a fraction of 700/1000, 700 and 1000 had a gcd of 1 and therefore the fraction could not be simplified. It's very strange though, sometimes it works and sometimes it doesn't. It is therefore difficult to set the correct answer as there is no predicting which answer itself has calculated.

b)ii) - I have had to create a number using individual variables which is causing problems, e.g. variable a = 1, variable b = 2, variable c = 3 and the full number = 123. Everything is fine up until the end where there is a fraction that needs to be simplified where 123 is the numerator. Numbas obviously won't recognise (1)(2)(3) as 123 so I don't know how to get around this. I could ask the students to just not simplify their answer which gets rid of the problem but Vicky and I both agree that is not best practice.