Back to Simple Interest Math
11+interest-growth

Rate — the percentage

Explore why interest = P×R×T.

In this lesson

Rate — the percentage is part of Simple Interest Math. This preview shows how interest-growth connects to everyday family decisions such as earning, saving, spending choices, goals, approvals, or parent-guided money conversations inside Progress Penguin.

Think about this money choice

Imagine this situation: Two savings accounts: Account A at 6%, Account B at 9%. You save 40000 in local currency for 1 year.

How it works

Interest = P×R×T. Rate and interest are directly proportional — double the rate, double the interest (with same principal and time). Comparing rates before saving or borrowing is always worthwhile.

Apply it to a real decision

Real-life money moment: You borrow 50000 in local currency at 24% APR for 1 year. A bank offers the same loan at 18% APR.

Activity preview

Connect the ideas

Use the lesson to complete this short practice activity.

Practice adding money to savings

Open Requests and make a deposit request into savings so you can see how saving starts. Parent approval can happen later.

Quiz preview

If a rate is 6% per year and you save for 1 year:

6% (0.06)
6 whole number
60%
0.6

Two savings accounts: Account A at 6%, Account B at 9%. You save 40000 in local currency for 1 year. How much more does Account B earn?

2400 in local currency
3600 in local currency
600 in local currency
1200 in local currency