AQA C4 Binomial expansion approximation help

I'm stuck on the approximation questions in binomial expansion, this is because they ask for 12 decimal places to display my answer, however, when I try to minus the following numbers, I can minus the first one however, the second one doesn't make a different since my calculator won't display to that level of accuracy.





How can I go about answering this question to 12 d.p?

Try counting the number of zeros in the final term you're subtracting! Will it actually make an answer to the 12th decimal place?

No that one won't, but for the second term it will and it won't change my answer if I minus 0.00000000015625

so I do 2 - 0.000025
and get 1.999975
then if I then minus 0.00000000015625
I get 1.999975
which is the same answer, it doesn't go past 6 decimal places :/

Well the blunt answer is "you should be able to do this on paper" - it's only primary school maths after all

Is this an actual exam question you're tackling, or an extension question from a text book?

Edit: just seen it's a "worked example"! So do they give you the working?

Alternatively, does it help to leave the 1st 3 terms as fractions and then use the calculator for the final simplification?