Repeated Percentages (Compound Interest): Probing Questions
Whether you are looking for a question to stimulate discussion in lesson, or a challenge at the end of a homework, then hopefully you will find these useful.
Contents
Convince Me That... keyboard_arrow_up
Back to Top
I use Convince Me That questions lots in my lessons and homeworks. Providing students with a statement and challenging them to come up with as many different ways of convincing you as possible can lead to some fascinating discussions. The different ways of seeing the same thing can also help improve the depth of students’ understanding. Thanks so much to the Thornleigh Maths Department, in particular Erica Richards, Anton Lewis and Gareth Fairclough for helping me put these together, and we will endeavour to keep adding more!
Compound interest rates on a bank account will earn more money than a simple interest rate of the same percentage.
If £200 is put into an account with a compound interest rate of 3.5%, and another £200 is put into an account with simple interest of 4% then the first account will have more money than the second after 9 years.
Increasing by 25% and then increasing by 50% is the same as increasing by 87.5% once.
Compound interest and graphs of exponential functions are related
VI3 Treatment keyboard_arrow_up
Back to Top
We devised VI3 Treatment as a versatile way of giving students meaningful follow-up work at once we have marked their homework. The idea is that students are challenged to come up with 3 things with certain constraints. These are ideal to use as an extension for students who have got everything correct, and also as further purposeful practise for students who have got a particular question wrong. Use the ideas below and adapt them accordingly, using different numbers where appropriate. Either mark them yourself or better still, get other students to do it. Thanks so much to the Thornleigh Maths Department, in particular Erica Richards, Anton Lewis and Gareth Fairclough for helping me put these together, and we will endeavour to keep adding more!
Write 3 compound interest questions which all have a time period of 3 years, which start with £150 and have a final answer between £160 and £210.