Introduction to Investing

Learn the basics of investing, including stocks, bonds, and how your money can grow over time.

Intermediate25 minLesson
Printable worksheet

Definition

Investing means putting money into something (like stocks, bonds, or funds) with the expectation that it will grow over time.
Unlike saving in a bank account, investing involves:
  • Higher potential returns (your money can grow faster)
  • Some risk (you might lose money)
  • Time (investments work best over many years)
The key equation for investment growth:
A=P(1+r)tA = P(1 + r)^t
Where:
  • AA = final amount
  • PP = principal (starting money)
  • rr = annual return rate (as decimal)
  • tt = time in years

Try it now

What is the main difference between saving and investing?

Worked Examples

You invest 1000 dollars at 7% annual return. How much will you have after 10 years?
1

Identify the values

P=1000P = 1000, r=0.07r = 0.07, t=10t = 10 → Principal, rate, time
2

Apply the formula

A=P(1+r)t=1000(1.07)10A = P(1 + r)^t = 1000(1.07)^{10} → Set up calculation
3

Calculate (1.07)10(1.07)^{10}

(1.07)10≈1.967(1.07)^{10} \approx 1.967 → Growth multiplier
4

Find final amount

A=1000×1.967=1967A = 1000 \times 1.967 = 1967 → About 1967 dollars

Common Mistakes

Confusing investing with gambling

Why it's wrong: While both involve risk, investing is based on research and long-term growth, not chance. Historically, diversified investments have always grown over long periods.

Correct: Think of investing as planting a tree - it takes time to grow, but it's not random. Gambling is like hoping for lightning to strike.

Thinking you need a lot of money to start

Why it's wrong: Many apps let you start with just a few dollars. The key is starting early, not starting big.

Correct: Even 25 dollars per month can grow to over 30,000 dollars in 30 years at 7% return.

Checking investments too frequently

Why it's wrong: Markets go up and down daily. Checking constantly causes anxiety and poor decisions.

Correct: Successful investors think in years and decades, not days and weeks.

Interactive Visual

Interest Calculator

Formula
Compound Interest:A = P(1 + r/n)^(nt)A = 1000 · (1 + 0.07)^10 = $1,967.15

Compound Interest

Interest Earned:$967.15
Total Amount:$1,967.15

Growth Over Time

yearsAmount

Pie Chart

Emma's 5000: stocks and bonds

Stocks(60%)
Bonds(40%)

Interactive Sandbox

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Practice Problems

15 problems
Problem 1 of 15
Easy
What is the main difference between saving and investing?

Why It Matters

Investing is one of the most powerful tools for building wealth over time:
  • Retirement: Most people need investments to afford retirement
  • Beating inflation: Money in a regular account loses value over time as prices rise
  • Compound growth: Your earnings generate their own earnings (the "snowball effect")
  • Financial goals: Buying a home, funding education, or starting a business
Starting early is crucial. A 20-year-old who invests 100 dollars monthly can end up with more than a 30-year-old who invests 200 dollars monthly, thanks to compound growth!

Real World Applications

Retirement Planning

Most retirement savings (like 401k or IRA accounts) are invested in the stock market to grow over decades.

Example:

If you invest 500 dollars monthly from age 25 to 65, earning 7% annually, you'll have about 1.2 million dollars for retirement.

1Try It Yourself

A company matches 50% of your retirement contributions up to 6% of your salary. You earn 50,000 dollars per year.

If you contribute 6% of your salary, how much total goes into your retirement account annually?

Step 1: Write the mathematical expression

Your contribution plus company match:

College Savings

Parents often invest money to pay for their children's future education.

Example:

Starting when a child is born, investing 200 dollars monthly at 6% return for 18 years yields about 77,000 dollars for college.

2Try It Yourself

Parents invest 5000 dollars when their child is born. College costs 100,000 dollars and is 18 years away.

If investments grow at 8% per year, will the 5000 dollars be enough?

Step 1: Write the mathematical expression

Calculate the future value:

Building an Emergency Fund

While emergency funds should be easily accessible, understanding growth helps set savings goals.

Example:

Having 6 months of expenses (about 15,000 dollars) invested conservatively can still earn 3-4% while remaining accessible.

3Try It Yourself

You want to build a 10,000 dollar emergency fund. You can save 400 dollars per month.

How many months will it take to reach your goal (without investment returns)?

Step 1: Write the mathematical expression

Calculate months needed:

Key Takeaways

  • 1Investing means putting money to work with the expectation of growth over time
  • 2The compound growth formula is A=P(1+r)tA = P(1 + r)^t
  • 3Stocks have higher potential returns but more risk; bonds are safer but grow slower
  • 4Diversification (spreading investments) reduces risk
  • 5Starting early is more important than starting with a lot of money
  • 6Time in the market beats timing the market - stay invested for the long term

Frequently Asked Questions

Saving puts money in a safe place (like a bank) with low returns (1-3%). Investing puts money into assets (stocks, bonds) with higher potential returns (5-10%) but also some risk of loss.
Saving puts money in a safe place (like a bank) with low returns (1-3%). Investing puts money into assets (stocks, bonds) with higher potential returns (5-10%) but also some risk of loss.
With diversified investments (like index funds), losing everything is extremely unlikely. Individual stocks can go to zero, but a diversified portfolio of hundreds of companies has never lost all value.
Financial experts suggest investing 10-20% of your income. Start with whatever you can afford - even small amounts add up over time thanks to compound growth.
As early as possible! A 20-year-old who invests just 50 dollars per month can have more at retirement than a 40-year-old investing 200 dollars per month, thanks to compound growth.

Glossary

Stock
Ownership share in a company. When the company does well, the stock value increases.
Bond
A loan you make to a company or government that pays you interest.
Portfolio
Your collection of all investments (stocks, bonds, etc.).
Diversification
Spreading money across many investments to reduce risk.
Return
The profit or loss on an investment, usually expressed as a percentage.
Risk
The possibility of losing money on an investment.
Compound growth
When your earnings generate their own earnings, creating exponential growth.
Today's challengeOne problem, three tries

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