Pick a currency and practise the three things every cashier does without thinking: count a pile of money, work out the change and hand it back with as few coins as possible.
Currency
A mixed pile of coins and bills appears. Add it up and pick the total. Tip: sort it in your head and start with the biggest pieces.
How much money is this?
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Progress
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Score
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Streak
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Accuracy
A customer pays for something. Work out the change, or switch to “Give change” and hand it back by tapping coins and bills — with as few pieces as you can.
Price—
Customer pays—
Money handed over
How much change is due?
Tap to add to the change
Change in your hand (tap a piece to take it back)
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Progress
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Score
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Streak
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Accuracy
Make the target amount by tapping coins and bills. Any combination that adds up counts, but the fewest pieces earns three stars.
Target—
Amount—
Tap to add
Your amount (tap a piece to take it back)
Coins and bills are simplified drawings with roughly the right size and colour, not the real designs.
Why count money by hand at all
Cards and phones handle most payments now, but cash has not gone away. Market stalls, tips, school fundraisers, taxis abroad and the first job behind a till all still run on coins and bills, and that is exactly where a slow or shaky count costs you — a queue builds up behind you, or you walk away a few coins short. Counting money is also one of the most practical places to use mental arithmetic: every sum has a real object attached to it, and the numbers are always friendly multiples of 1, 5 and 10.
This page lets you practise with four currencies whose coins and bills look and behave differently: the US dollar, the euro, the Korean won and the Mexican peso. Travellers can get used to a currency before the trip, cashiers can warm up before a shift, and anyone learning the language of numbers in English, Korean or Spanish can hear how amounts are said and written.
Count the biggest pieces first
The single most useful habit is to sort before you add. Group the bills, then the large coins, then the small ones, and count from the largest value down while keeping a running total in your head. Big pieces get you close to the answer quickly, and the small coins only adjust the last digits, so a slip there costs little. Counting in the order the money happens to lie forces you to jump between scales — a $20 bill, then a dime, then a $5 bill — and that is where most mistakes come from.
Within a group, count by the value rather than one by one: quarters go 25, 50, 75, one dollar; 500-won coins go 500, 1,000, 1,500; 20-cent euro coins go 20, 40, 60, 80, one euro. When you answer a question in the first tab, the explanation shows exactly this running total, group by group, so you can compare it with the way you counted.
When size and value disagree
Coins are not always ordered by size. The US dime, worth 10 cents, is the smallest US coin — smaller than both the penny and the nickel. In the euro series the 10-cent coin is smaller than the 5-cent coin because it belongs to a different, gold-coloured set, and the €1 coin is slightly smaller than the 50-cent coin. Korea's 10-won coin shrank in 2006 and is now smaller than every other coin in use. Mexico is friendlier: its coins grow steadily from 50 centavos up to the large bimetallic 20-peso coin.
That is why the drawings on this page keep the rough proportions and colours of the real coins: recognising a coin at a glance, without reading it, is half of counting fast. The pictures are deliberately simple — no portraits or official designs, just size, colour and value — so treat them as a map of the system rather than a copy of the money.
Making change by counting up
Subtraction is the obvious way to find change — $10.00 minus $6.35 is $3.65 — but it is also where borrowing errors creep in: a hurried 10.00 − 6.35 easily becomes $4.75 or $3.75. Experienced cashiers avoid the subtraction altogether. They start at the price and count up to the amount paid, adding the smallest coins first to reach a round number: $6.35, plus a nickel makes $6.40, plus a dime $6.50, two quarters $7.00, then three dollars to $10.00. The coins they used are the change, and the customer can follow every step.
The second tab drills both halves of this skill. In “How much change?” you choose the amount, and the wrong options are the typical slips: a digit subtracted without borrowing, or an answer off by ten or by one whole unit. In “Give change” you tap the coins and bills you would actually hand over. The feedback always shows the counting-up sequence, so you learn the cashier's route rather than just the result.
The fewest coins, and why the computer checks
Handing back change with as few pieces as possible is polite and keeps the till stocked. The usual rule is greedy: take the largest coin or bill that still fits, then repeat. For the four currencies here that rule always gives the true minimum, because their values were chosen so that it would — 1, 2, 5 in each decade for the euro and the peso, 1, 5, 10, 25 for US coins, and 1 and 5 in each decade for the won.
It is not a law of nature, though. With coins worth 1, 3 and 4, the greedy rule pays 6 as 4 + 1 + 1, three coins, while 3 + 3 needs only two. Old British money, with its 3-penny and 6-penny pieces and half-crowns, had traps of this kind. So this page does not trust the shortcut: it finds the minimum with dynamic programming, which tries every amount from the bottom up, and grades your answer against that. In the third tab, the exact amount with the fewest pieces earns three stars, one or two pieces more earns two, and any other correct combination earns one.
Four money systems at a glance
US dollar — coins of 1, 5, 10 and 25 cents (penny, nickel, dime, quarter) and bills of $1, $5, $10, $20, $50 and $100, all the same size. The US Mint stopped making new pennies in 2025; they remain legal tender, but some shops now round cash totals to the nearest 5 cents.
Euro — eight coins from 1 cent to €2 and bills of €5, €10, €20, €50 and €100 that grow with their value (€200 exists but is rare, and €500 is no longer issued). Several euro countries, including Finland, the Netherlands, Belgium, Ireland, Italy, Slovakia and Estonia, round cash totals to the nearest 5 cents.
Korean won — no subunit; coins of 10, 50, 100 and 500 won and notes of 1,000, 5,000, 10,000 and 50,000 won (the 50,000-won note arrived in 2009). Prices are often whole hundreds or thousands, so the 10-won coin is rarely needed in shops.
Mexican peso — coins of 50 centavos and 1, 2, 5, 10 and 20 pesos (the larger ones bimetallic) and polymer and paper notes of 20, 50, 100, 200 and 500 pesos; a 1,000-peso note also exists. Twenty pesos comes as both a coin and a note, so the page shows both. Smaller 10- and 20-centavo coins exist but are rarely handled, so 50 centavos is the smallest piece here.
How the practice is built
Every amount is generated fresh and calculated in whole cents, won or centavos, so there are no rounding surprises like 0.1 + 0.2 = 0.30000000000000004. In the counting tab, the wrong options come from the mistakes people actually make: missing one piece, counting one twice, or confusing a coin with its neighbour — a quarter read as a dime, a 500-won coin as a 50. In the change tab, the first level pays for a small item with a single coin or bill, the second with a bill, and the third adds a classic cashier's trick: the customer hands over extra coins so the change comes back as round bills.
A short routine that works
Five minutes a day is plenty. Start with one round of counting at the level that feels easy, then one round of change in “How much change?” mode, and finish with a round of “Give change” or building amounts, aiming for three stars. Once the easy levels are automatic, hide the running total in the third tab so you have to keep the sum in your head, or switch currency: counting in a system you do not use every day is the quickest way to find out whether you really understand place value or have only memorised your own coins.
US dollars, euros, Korean won and Mexican pesos. The page starts with the currency that matches its language (dollars in English, won in Korean, pesos in Spanish), and the choice is remembered on your device.
Are the coins and bills real images?
No. They are simple drawings that keep the rough size, colour and value of each piece so you can recognise it at a glance. There are no portraits, security features or official designs.
What is the fastest way to count a pile of money?
Sort it, then count from the largest value down while keeping a running total. Count each group by its value (25, 50, 75, 100) rather than one by one. The explanation after each question shows that running total so you can check your method.
How does “counting up” for change work?
Instead of subtracting, start at the price and add coins and bills until you reach the amount paid, smallest first. For a $6.35 item paid with $10: a nickel to $6.40, a dime to $6.50, two quarters to $7, three dollars to $10 — $3.65 in change, with no subtraction.
How are the stars in “Build an amount” decided?
The page computes the smallest possible number of pieces for the target with dynamic programming. Matching that number earns three stars, using one or two extra pieces earns two, and any other combination that adds up exactly earns one.
Is it free, and does it work on a phone?
Yes to both. There is no sign-up, everything runs in your browser, and the coins and bills are sized for tapping on a small screen.