How to learn with this course

Most founders learn startup funding at the worst possible time: the week before they sign. This course lets you learn it earlier. You make small mistakes in problems, not large mistakes in contracts. This first lesson shows how the course works, and why it asks you to do more than you read.

Start with a question about memory. Which plan gives better memory one week later: study a text in four sessions, or study it in one session and test yourself three times?

Predict first

In a 2006 study, students who read a short text approximately 14 times remembered 40% of it one week later. A second group read it approximately 3.4 times and then did three recall tests. What percentage did the second group remember?

Type a guess before you continue. A guess first, even a wrong one, makes the answer easier to remember.

Why a self-test works better than a second read

When you test yourself, you must find the idea in your memory without the text in front of you. That effort is the practice, and its name is retrieval practice. A second read gives you the idea again, so you do not have to find it.

Dunlosky and his colleagues (2013) rated ten study methods. Only two got a “high utility” rating: practice tests and practice that you spread over time. A second read, highlights, and summaries got a low rating. In a review of 225 studies, Freeman and his colleagues (2014) compared lecture courses with courses that use active learning. The failure rate was 33.8% in lecture courses and 21.8% in courses with active learning.

The loop in each lesson

Each lesson uses the same loop, so that you always know what comes next. The table shows each part, what you do, and why the part is there:

Part	What you do	Why it helps
A question	Read a question or a headline that you want to understand	A question gives the lesson a purpose.
Predict first	Type a guess before you see the answer	A committed guess makes the answer easier to remember, also when the guess is wrong.
Short explanations	Read one idea at a time, each with a numeric example	A number lets you do a check of each idea.
Worksheets	Move the numbers in a widget and read what they mean	You see how the full system responds, not one example only.
A worked example	Show one step at a time, and try each step in your head first	Beginners learn more from solved examples than from problems without help.
Work it out	Do the last steps of a problem yourself	The steps that you do yourself move you from examples to full problems.
Quiz	Answer 4 to 6 questions and read the feedback	A test with feedback stays in memory longer than a second read.

Several parts come from research results. Hohman and his colleagues (2020) describe a study in which a prediction that learners drew made their recall better. Nicky Case calls this pattern “Place Your Bets.” Renkl and his colleagues (2002) studied worked examples. They removed the solved steps one at a time, and learners did better on similar problems than after a sudden change to full problems.

Why the feedback names your error

Each wrong option in a quiz is a mistake that founders make. When you select it, the feedback tells you which error you made, for example: “This divides by the pre-money valuation.” The feedback does not only say “Try again.”

This choice is important. In a review of 607 effects, Kluger and DeNisi (1996) found that more than one third of the feedback in the studies made performance worse. Feedback about the task helps more than praise (Hattie and Timperley, 2007). Feedback after a multiple-choice test also decreases the risk that you later remember a wrong option as correct (Butler and Roediger, 2008).

Spread your reviews over time

Your chance to remember a new idea decreases fast at first, and then more slowly. One model of this decrease comes from Settles and Meeder (2016), who used it to schedule reviews at Duolingo. In the model, your chance to remember an idea halves with each “half-life” that passes. Move the numbers to see how fast the chance decreases.

Model

How fast you forget a new idea

In the half-life model, your chance to remember an idea halves with each half-life that passes. Change the half-life and see when a review is due.

Half-life of the memory, in days4

Days until the chance to remember falls to 50%.

Review when the chance falls to80%

Chance after 1 day: 84%
Chance after 1 week: 30%
Review is due after: 1.3 days

With a half-life of 4 days, you remember a new idea after one day with a chance of 84%, and after one week with a chance of 30%. To keep the chance at 80% or more, review after 1.3 days.

The review deck of this course also spreads reviews over time. A card that you know waits longer each time before it comes back: 1 day, then 3, then 7, then 21 days.

The best time for a review depends on how long you want to remember. Cepeda and his colleagues (2008) tested one review before a final test:

For a test one week later, the best gap was approximately 20% to 40% of that week: 1.4 to 2.8 days.
For a test one year later, the best gap was approximately 5% to 10% of the year: 18 to 37 days.

Do the math for two cases yourself.

Work it out

An idea has a half-life of 4 days. What is your chance to remember it 8 days after you last practiced it?

Work it out

You want to remember an idea for one year. The best first review comes after 5% to 10% of that time. What is the earliest of those days, in days after the lesson?

The review deck of this course uses spaced repetition. When you complete a lesson, its terms go into your deck. A card that you know waits longer before it comes back: 1 day, then 3, then 7, then 21 days. A card that you miss starts again at the first step.

How to use the worksheets

Each lesson has one or more worksheets. A worksheet is a small calculator with an explanation that changes with the numbers. Use each worksheet like this:

Read the title and the first sentence. They tell you what the worksheet shows.
Before you change a number, say what you think will change.
Change one input at a time.
Read the gray explanation under the numbers. It changes with each input.
Try the extremes: a very small value and a very large one.

You can type short values in a number field, for example 1.5M, 250k, or 20%. Each slider also moves with the arrow keys. Many calculators in the course also have their own page in the calculators list, for when you want the tool without the lesson.

Other parts of the course

The course has three more tools:

The glossary. A word with a dotted underline, such as dilution, has a definition. Put the pointer on the word to read it, and click the word to open the glossary. On a phone, tap the word one time to read the definition.
The review deck. The review deck shows the terms of the lessons that you completed, on the schedule above.
Your progress. The button at the end of each lesson marks the lesson as complete. Your progress and your quiz scores stay in your browser. Nothing goes to a server.

How this course treats facts

Startup funding changes fast, so the course is strict about its numbers:

Each market number has a period, for example “In Q2 2026, the median seed round was …”. Each lesson lists its sources at the end.
When two data sources give different values, the lesson shows the two values and tells you why they are different.
The companies are invented. Northwind Labs, with its founders Ada and Ben, is in examples across the course.
Legal and tax rules have a date. Speak to a lawyer or a tax professional before you act on one.
The course does not sell a product, and it names the conventions behind each calculation.

The next lesson, the whole story in one sitting, follows Northwind from two founders to a sale. It gives you a map of the full course.

Check yourself

These four questions are about this lesson.

Quiz · question 1 of 4

Test what you learned

You have one month to learn SAFE math. Which study plan gives the best memory at the end of the month?

Pretest: what do you know today?

This pretest has 10 questions from across the course. Most of them are about lessons that you did not read yet, so expect some wrong answers. Wrong answers are also useful. A test before a lesson makes later learning better, if feedback comes after it (Richland, Kornell, and Kao, 2009).

Do not look up the answers. Guess, then read the feedback for each option. The capstone module ends with a final exam of the same type, so that you can compare your two scores.

Quiz · question 1 of 10

Pretest: 10 questions from the full course

You hold 5,000,000 of the 10,000,000 shares of a company. The company issues 2,500,000 new shares to an investor. What part of the company do you own now?

Your score today is a start point, not a grade. Each question that you missed has a lesson in this course that answers it.

In this lesson you will learn