Money: crowns and paying · 마틴과 코딩하기

Crowns are counted for real

Money is maths you meet every day. In a shop, at the ice cream stall, with pocket money.

Czech coins: 1 Kč, 2 Kč, 5 Kč, 10 Kč, 20 Kč and 50 Kč. 메모s start at a hundred: 100 Kč, 200 Kč and on.

With money you do two counting jobs. You make an amount: ice cream costs 25 Kč — you give a 20 Kč coin and a 5 Kč coin. You count the change: you pay with a 50 Kč coin, ice cream costs 25 Kč, the seller gives 25 Kč back.

Why learn this when people pay by card today? Because pocket money comes in coins. A school fair takes coins. An ice cream stall does too. And most of all: anyone who can count the change can tell when they get too little back. Counting is the best guard of a purse.

Change is ordinary subtracting: 50 − 25. Or filling up: from 25 to 50, 25 is missing. You already know both. Today we just pour it into a purse.

Sofie buys a pancake at a stall for 38 Kč. In her purse she has a 50 Kč coin. “Fifty,” she hands over the coin. The seller counts the change out loud by filling up: “Thirty-eight… and two Kč is forty… and ten is fifty.” She hands Sofie a 2 Kč coin and a 10 Kč coin. Sofie checks in her head: 2 + 10 = 12. And 38 + 12 = 50. It matches. “Thank you!” At home she shows Adam: “Sellers count up. It is faster than subtracting.” Adam wants to practise at once. They take out the money box and play pancake stall. Whoever gives the right change may keep a paper crown.

💡

Count change by filling up: from the price to the coin you paid with. First fill to ten, then in tens.

Making amounts and giving change

Making an amount. You want to pay 27 Kč. Make it from the biggest coins: a 20 Kč coin (20), a 5 Kč coin (25), a 2 Kč coin (27). Three coins. An amount can always be made in more ways — even 10 + 10 + 5 + 2. Fewer coins = smarter paying.

Counting cash. How much do you have in your purse? Add from the biggest: 20 + 10 = 30, plus 5 is 35, plus 2 is 37 Kč.

Change. Price 38 Kč, you pay 50 Kč. How much do you get back?

Subtracting path: 50 − 38 = 12.

Filling-up path (that is how sellers do it): from 38 fill to a full ten — 2 Kč, you are on 40. Then in tens to fifty — 10 Kč. Together 2 + 10 = 12 Kč back.

Check: price + change = what you paid. 38 + 12 = 50. If it does not match, someone slipped.

And one rule outside counting: count your money before the shop and pay in peace. Rush is the dearest thing in a shop.

Make 43 Kč from as few coins as you can

I go from the biggest coin that fits.

A 20 Kč coin: I have 20. One more 20 Kč coin: 40. 3 Kč are left.

A 2 Kč coin: 42. A 1 Kč coin: 43.

In all: 20 + 20 + 2 + 1 = 43 Kč. Four coins.

Check by adding: 20 + 20 = 40, 40 + 2 = 42, 42 + 1 = 43. It matches.

A notebook costs 24 Kč. You pay 50 Kč. How much do you get back?

I fill up from the price.

From 24 to a full ten: 24 + 6 = 30. That is 6 Kč.

From 30 to 50: two 10 Kč coins, 20 Kč.

Together: 6 + 20 = 26 Kč back.

Check: 24 + 26 = 50? Tens 20 + 20 = 40, ones 4 + 6 = 10, in all 50. It matches.

You have 30 Kč. Is it enough for an ice lolly at 18 Kč and chewing gum at 15 Kč?

First I add the prices: 18 + 15.

Tens: 10 + 10 = 20. Ones: 8 + 5 = 13. In all 20 + 13 = 33 Kč.

I compare with the purse: 33 > 30.

It is not enough. I am missing 33 − 30 = 3 Kč.

I have to pick one, or wait for pocket money. A purse can say no — and counting tells it that before you stand at the till.

⚠️

The value of a coin is not the number of coins! One 20 Kč coin is more money than five 1 Kč coins, even though there are five coins. Always count Kč, not pieces of coin.

Play it

Before you go to the sheet, try it with your eyes. This is not a test — it is a game. Tap until you see it.

Practice: now you do it 🎲

Now try it for real. You will see all the questions at once, like on paper. 시작 with ten. If it goes well, add more.

Pay and count the change. You can see the coins above.

Practise the questions

On paper

Paper, a pencil and real or paper coins. Play shops with a parent.

Make the amounts 36 Kč, 58 Kč and 71 Kč from coins. Write which coins you used.
Shop game: a parent is the customer and pays you 50 Kč for goods at 32 Kč. Count the change by filling up out loud.
Calculate: is 40 Kč enough for two things at 22 Kč and 15 Kč? Write the whole calculation.
Tip out the money box (with permission) and count how much is in it. From the biggest coins.

Now you 💪

I know Czech coins and I can make an amount from them.
I count change by filling up from the price.
I check: price + change = what was paid.

✅

Done when: In the shop game you give the right change three times and the check matches each time.

What to take from this lesson

Coins: 1, 2, 5, 10, 20, 50 Kč. 메모s from 100 Kč.
Make an amount from the biggest coins.
Change = filling up from the price to what was paid.
Check: price + change = what was paid.
Count Kč, not pieces of coin.