A model is not guessing
Guessing: “I’ll probably have a hundred left.”
A model: you change one number at the top and you see what it does to the balance.
You do not recalculate twenty formulas. You do not write a second workbook “just in case”. You change a lever. The table finishes the count.
Two useful numbers on Kapesne:
- Plan / reserve — how much you want to take aside. Say 10%. You already have that in F1 from the dollar address.
- Pessimist — spending 20% higher. A second field. Say F2 =
1.2. It means: calculate spending times 1.2.
You do not need two copies of the whole table. You need inputs at the top and formulas below. Inputs are numbers you type. Outputs are numbers a formula calculates. Do not mix them.
Two levers, one sheet
Leave E1 Reserve, F1 10% (inside 0.1). Add a second row:
| E | F | |
|---|---|---|
| 1 | Reserve | 10% |
| 2 | Pessimist | 1.2 |
F2 is a multiplier. 1 = real spending. 1.2 = a fifth worse week. 1.5 = a really bad week.
Spending in C2 = 20, C3 = 15, C4 = 10.
-
On
Kapesneleave the reserve in F1. In E2 writePessimist. In F2 write1.2. Leave the format as a number, not as a percent. It is a multiplier, not twenty percent in a mask. -
In H1 write
Bad spending. In H2:=C2*$F$2Enter. 20 × 1.2 = 24. You must see 24. If you see 20, F2 is 1 or empty. If you see 2400, F2 has percent format and inside is 1.2 as 120%.
-
Drag H down. H3 = 18. H4 = 12. Click H4. In the formula
$F$2, not$F$5. The dollar from last time. Without it the pessimist is dead from the third day. -
Rewrite F2 to
1. Column H must drop to 20, 15, 10 — the same as C. The pessimist vanished. Rewrite F2 to1.5. H is 30, 22.5, 15. A worse week. You did not change any formula in H.
You can take the reserve off the bad spending, not the real one. For example =C2*$F$2*$F$1 — ten percent of the inflated spending. Two dollars, two levers. First be able to do each separately. Then you join them.
What you should see when you move F2
Leave C2 = 20, C3 = 15, C4 = 10. H = =C2*$F$2 dragged down.
| F2 | H2 | H3 | H4 |
|---|---|---|---|
| 1 | 20 | 15 | 10 |
| 1.2 | 24 | 18 | 12 |
| 1.5 | 30 | 22.5 | 15 |
If a number in the table does not match this, F2 has the wrong format, or H is missing a dollar. Click H3. $F$2 must light up.
Total of bad spending: under H, say H9, =SUMA(H2:H4) / =SUM(H2:H4). Switch F2 — the total must move. That is the scenario output. Write that into a sentence on Poznamky.
What if: one sentence with a number from the table
A model ends with a sentence, not a feeling.
On Poznamky write: “If the reserve is 20%, I will have ___ Kč left.”
Steps:
- Switch F1 to 20% (
0.2). - Look at the balance or at the total of column G (taken off) and D (left) — according to what you have.
- Into the sentence write that number from the cell, not a guess.
- Put F1 back to 10%, if 10% is your plan. Let pessimistic 20% stay in the sentence, so you know what you tried.
That is a scenario. You changed an input. You read an output. You did not copy the workbook.
Do not copy the whole workbook as Kapesne-pesimista. In a week you do not know which is the truth. One table, two levers. When you want to save a result, write a sentence on Poznamky or download a PDF. Let data have one home.
What often goes wrong
F2 as a percent. You write 1.2, turn on %. You see 120%. The formula multiplies by 1.2, sometimes even 120 depending on what is inside. Leave the multiplier as a number. Leave the reserve as a percent. Two levers, two formats.
No dollar. =C2*F2 you drag down, F2 becomes F3. H3 is zero. F4 on F2.
A lever down among the days. Let F1 and F2 stay above the table or next to the headings. If you stick them in row 10, you sort them with the days by mistake.
Three workbooks. “Normal”, “bad”, “really bad” as copies. You change income in one, in the other not. The model dies. Go back to F2.
🏆 Mini dashboard — scenario
On the dashboard later put only F1 and F2 as “controls” and three results (total of bad spending, reserve, balance). The class sees levers, not twenty formulas. A link from the dashboard to Kapesne!F1 — the Workbook boss can do that. For now let the levers live on Kapesne and work.
💰 Pocket money — two weeks in one table
F2 = 1 is this week. F2 = 1.2 is “what if ice cream”. You do not have to create a sheet Tyden2. The same days, a different lever, a different sentence on Poznamky.
Now you 💪
First: F2 = 1.2, column H = =C2*$F$2. Three days, three worse numbers. F2 to 1, H = reality. F2 to 1.5, H somewhere else again. Do not touch the formulas in H.
Second: on Poznamky one sentence: “If the reserve is 20%, I will have ___ Kč left.” Take the number from the table after changing F1, not from your head. Add a second sentence: “If spending is × 1.2, bad spending for the week is ___ Kč.” Total of column H.
Two sentences, two levers, one workbook.
Check: You change two cells at the top, not twenty formulas. H4 still shows $F$2. That is the Modeller.
What to take from this lesson
- A scenario = change an input, watch the output. Levers at the top, calculations below.
- Reserve is a percent (
0.1). Pessimist is a multiplier (1.2), not a percent. - One table, not three copied workbooks. Write a sentence with a number on
Poznamky.
© 2026 Ing. Martin Polak / AlgoRhino · Điều khoản sử dụng nội dung