Model 1: Basic Compound Interest Calculations

04 Try it yourself Interactive

The direct model, period by period

This is the same engine as the introduction lesson, and here it is for practising the recognisable multipliers. Set a principal, rate and time, and note the amount — then cover the principal and see whether you could recover it from the amount alone. That is exactly the exam task.

₹1,000 at 10% for 3 years

A 1,331 = 11³

Watch the balance figures: 1,210, 1,331 and 1,728 all appear here and all are standard exam amounts precisely because they are clean powers.

Press Next to work through it one step at a time.

Rate / period–

Periods–

Interest–

Balance–

step 0 / 0