Graphics Calculator Resources for Years 9 and 10
Year Group 9
1 and 2
Sub-Strand Consumer Arithmetic
Stephen Arnold, Module FM1 in Integrating Technology
in General Mathematics, T3 Publication, 2003.
Modified by Peter McIntyre (email@example.com).
Calculators Texas Instruments TI-83 family
Description An introduction to compound-interest calculations on a
graphics calculator using formulas, tables and graphs.
Integrating Technology in General Mathematics is available at
Compound Interest — Worksheet
(a) If you invest $5000 at an annual rate of 6% compounded annually, how much
money will you have after 5 years? after 10 years?
(b) What calculation does the calculator perform each time you press ENTER (except
for the first time)?
(c) Write out the calculation steps as the calculator does them to find the amount of
money after 5 years. Turn this into a formula involving a number raised to power
5 and hence do the calculation on the calculator the normal way to check your
How long does it take to double your money?
(a) Make up a table of the values of N you tried and the amount of money you found
with each N . Identify which N answers the question and show that it does.
(b) From the calculator table, by the end of which year does your money double?
If you invest $5000 at 6% annual interest, compounded monthly, how long does it take
to double your money?
(a) Explain how you modify the formula to allow for monthly compounding periods.
(b) In which year does the amount double now?
(c) Compare Y1 and Y2. What does each column represent? Which compounding
method is better?
If the annual interest rate is 8% compounded monthly, in which year does the amount
By the beginning of which month of the ninth year does the amount double if the annual
interest rate is 8% compounded monthly?
(a) Do we have to change the formula to answer this question?
(b) At t