Income, spending, balance

Three words: it came, it left, it remains

Income is a token that came. Spending is a token that left. Balance is what is left now — not what you had in your head on Monday. When you mix those three words up, the notebook will look full and the pocket empty.

The course does not want you to be a firm’s bookkeeper. It wants you to stop saying “it vanished somehow”. Nothing vanishes. Either it came, or it left, or it is still there. A fourth option is a lie.

Ema gets 100 Kč on Friday (income). She buys juice 25 and a sticker 40 (spending 65). In the pocket 35. Adam asks: “How much do you have?” Ema says “a hundred, I got a hundred.” That was Friday morning. Now it is 35. Balance is not a memory of income.

Adam has 0 in his pocket and says “I didn’t spend anything, I only lent it”. A loan is spending until it comes back. If it comes back, that is income. Until then, the balance is smaller. Words have to fit the coins, not a wish.

Now, not a memory

Income has a source: a parent, a gift, a returned loan, a reward for a task. 名前 the source. “From the air” is not a source. Spending has the name of a thing. “Various” is fog. Balance is income minus spending in the time you are watching — plus what you already had at the start.

The start matters. When on Monday you have 20 and on Friday 100 comes, the balance after spending 30 is not 70. It is 90. People forget the twenty in the bowl. Or they count the twenty twice. That is why the start is written once.

These three words hold for coins and for a purchase in a game. Game spending is spending of family tokens when a card runs. It belongs in your pocket-money notebook when it came from your promised pocket money. When a parent paid outside pocket money, it is family spending — in your notebook write “a parent paid, not from mine”. Honesty, not a formula.

Balance cannot be less than zero in a pocket with coins. You can owe — that is another lesson. When you get −20 and nothing in the pocket, the notebook says you forgot spending or invented income. Look for the mistake. Do not rewrite zero as a hundred to make it pretty.

Ema wants to shorten it to “it will be fine somehow”. Adam asks what the lesson Income, spending, balance is for, when a table can do a sum. A sum does not count respect, a PIN, a trap or an envelope. The core is: Income came, spending left, balance is what is left now.

スタート 20. Income 100. Spending 25 + 40. Balance 55. Ema has it on paper. In the pocket 35. 20 is missing. She found it in a coat. Now 55 fits. If she had not found it, she would look for unwritten spending. She must not add “income 20 from the air”.

Adam: income 0, spending 0, start 0. Balance 0. That is not shame. That is truth. Zero is a word, not mockery.

Why this right now

You are in the course Money with Martin, level Cashier. You can write numbers in a notebook or a table, but the topic is money and decisions, not Excel formulas. The account, the card and the PIN belong to a parent. A child’s email does not belong here. Do not put pocket-money numbers on the network.

This is not the Sheets with Martin course. A table may help, but the mark of success is a decision, not SUM.

You will know this lesson by one sentence: Income came, spending left, balance is what is left now. When you can say it to a parent or a teacher, you have the core. The rest is practice, not magic.

The whole of Cashier stands on three words. Without them an envelope and a goal of 200 Kč are only a wish. With them you can say why a goal will not work, without lying that “there was nothing”.

Four things you will build from the course

The course has four small projects. You do not have to do them all at once. Today you add only what this lesson can do.

Workshop: one day, three words

Take today or yesterday. Practice numbers if you do not remember — mark them with the word estimate.

1. Write the start (how much there was in the morning). If you do not know, write “I don’t know” and count the pocket now as the start from now.

2. Income: a list. Spending: a list. Both with Kč.

3. Count the balance. Count the pocket. If they do not match, look for a hole. Do not top up income.

4. One sentence to a parent: “Balance is what is left, not what I got.” No number on the network.

You count when you can do three words on one day. When pocket and paper do not match, the hole is a task, not shame. Shame is rewriting the paper so the pocket does not have to exist.

Practice: which word?

Match them. Practice numbers.

1. Friday 100 Kč from a parent. Income, spending, balance?

2. Juice 25 Kč. Which word? How does the balance change when the start was 100?

3. Ema says “I have a hundred”, but in the pocket 35. Which word did she mix up?

4. A loan to a friend 20 Kč. Why is that spending now?

Now you 💪

Go through three checks. By each one, tick in your head: do I see it, or not?

1. I can say three words with no Excel formula.
2. Balance is now, not a memory of income.
3. When paper and pocket do not match, I look for a hole, I do not invent income.

If something is missing, go back to the steps above. It is not a test for marks. It is a safety net, so you go on with certainty, not with a mess.

What to take from this lesson

• Income came. Spending left. Balance remains now.
• The start is written once. Otherwise a twenty gets lost or doubled.
• Zero is truth, not shame.
• Pocket-money numbers do not belong on the network.
• 名前s in the examples (Ema, Adam) are made up. Do not put your number, email or photo here.
• Next lesson: When you can do this, go to the next lesson in the same level.

© 2026 Ing. Martin Polak / AlgoRhino · コンテンツ利用規約