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Secondary maths teachers - does this homework make sense?

28 replies

PointyChristmasFairyWand · 04/12/2013 19:14

DD1 has just spent an hour working out the cube root of 426 to 2 decimal points. She's convinced that she has to do all the calculations by hand - no calculators allowed. She understands the method perfectly well - work out between which two whole numbers it falls, then work out between which two numbers to one decimal it falls, then down to the 2 decimal point numbers.

She has spent an hour on one sum and has 2 more to do. One of them isn't a cube, it's a fourth power.

I don't see the point of doing it all by hand. I really, really don't. Everything I have looked up suggests that 'doing it by hand' will still involve using a calculator for the individual sums. Am I being dim? Is there a possibility that my DD has misunderstood and that it's OK to use a calculator for the 7.52x7.52x7.52 etc.? I get that it's useful to practice multiplying decimals, but this?

OP posts:
starkadder · 05/12/2013 21:41

Love this thread (although do not understand much about maths). Someone should show it to those journalists who think MN is all about beakers/bumsex/nappies....

PointyChristmasFairyWand · 05/12/2013 21:44

Grin starkadder but what boring headlines that would make...

'MumsNet mathematicians in teacher challenge'

Hmm, maybe not so bad...

OP posts:
friday16 · 05/12/2013 22:57

don't use the cube root button

I use vintage RPN calculators which rely on you knowing that the cube root of x is x to the power 1/3. But I've just looked at my kids' modern calculators and I see they have a dedicated cube root key, and a dedicated nth root key as well. Luxury!

Everyone should use God's Own Calculator, accept no substitute. Especially as using a calculator that doesn't have an equals key stops anyone from borrowing it.

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