You are Here: Home >< GCSEs

# How important is it to remember maths formulas

Announcements Posted on
Why bother with a post grad course - waste of time? 17-10-2016
1. I am going through the CGP maths GCSE books and it says to remember the formula N = N0(1+r/100)n. No maths teacher has ever told me to remember it, is it really necessary to learn? Also I can answer compound interest questions without this. Thanks
2. U dont need to learn that... ive never seen that formula till now and most of the complicated equations that u need to know are on the first page
3. You may have to remember it, however, once you do a couple of questions on that topic (Compound growth and decay I believe it is), you'll think there never was a formula for it. It looks quite complex but it's really not.
4. If, given a problem like you have £20 in the bank and you get 30% interest at the end of the year (does such a bank exist? ), I suspect that your method to find the amount you have at the end of the nth year would be to find 30% of 20, then add it on, find 30% of the new amount and then add it on until you reach the nth payment.

Finding 30% of 20 is the same as doing (30/100) * 20, and then you are adding this on to the original amount, which is 20. If you were to make this look better, this would be 20(1 + (30/100)), which is the same as N0 (N0 meaning the amount you start with) * (1 + r/100), where r is the interest rate, 30%.

You can find the amount at the end of the next year as well by multiplying N0(1-(r/100)) (which is 20 *(1-(30/100))) by multiplying, and this is just a much faster way of doing it.

Have a look at past papers for your exam and see which way they prefer you to use it.

## Register

Thanks for posting! You just need to create an account in order to submit the post
1. this can't be left blank
2. this can't be left blank
3. this can't be left blank

6 characters or longer with both numbers and letters is safer

4. this can't be left empty
1. Oops, you need to agree to our Ts&Cs to register

Updated: May 2, 2016
TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Today on TSR

### How does exam reform affect you?

From GCSE to A level, it's all changing

Poll
Useful resources

## Study tools

### Essay expert

Learn to write like a pro with our ultimate essay guide.

See where you can apply with our uni match tool

### Make study resources

Create all the resources you need to get the grades.

### Create your own Study Plan

Organise all your homework and exams so you never miss another deadline.

### Resources by subject

From flashcards to mind maps; there's everything you need for all of your GCSE subjects.

### Find past papers

100s of GCSE past papers for all your subjects at your fingertips.