Practise counting US coins: count a handful, make an amount on a tray, or give change, at three levels.
Practice
Question 1 of 10
Right first time 0
Your best -
Coin key
Count the coins: pick the total, or type it as cents (35) or dollars ($1.35). Make the amount: tap coins to put them on the tray; tap a coin on the tray to take it off. Give change: work out what you give back and put those coins on the tray. A question counts as right first time if you did not use help, did not guess wrong, and (for the tray) did not go over. There are 10 questions in a round, and nothing is ever lost.
Every amount is a whole number of cents, so 35 cents is 35 and $1.35 is 135. Nothing is ever a decimal fraction inside the game, which means there are no rounding errors: the total of the coins is always an exact sum. The page turns the number into 35¢ or $1.35 only when it shows it.
The fewest coins for an amount is found by trying every coin for every smaller amount (dynamic programming). With pennies, nickels, dimes, quarters and dollars, taking the biggest coin first gives the same answer, so that is how a way to make an amount is shown.
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Choose a kind of practice and a level. A round is ten questions. There is no timer and nothing is ever taken away: you can always try again, and every question ends with a short, specific message about what you did.
Count the coins. A handful of coins is shown, biggest first at the Little and Middle levels. Pick the total from four choices. At the Big level you type the total instead, as cents (35) or as dollars ($1.35). If you pick or type the wrong total, you are told whether the coins add up to more or less than your guess, and you can try again. The Help me count button counts along the coins for you, with a running total after each one.
Make the amount. An amount is shown, such as 35 cents. Tap the coins in the purse to put them on the tray. The tray shows what you have and what you still need. Tap a coin on the tray to take it off, or use Take one off and Clear the tray. When the tray is exactly right the question is done, and you are told whether you used the fewest coins possible. The tray holds up to 24 coins.
Give change. A price is shown and what you paid with. Work out the change and put those coins on the tray. At Little you pay with a nickel or a dime, at Middle with a one-dollar rectangle for prices from 5 to 95 cents, and at Big with whole dollars (up to five of them) for prices from 31 cents to $4.99.
Levels.
| Level | Coins | Count the coins | Make the amount |
|---|---|---|---|
| Little | penny, nickel, dime | up to 30 cents | 2 to 30 cents |
| Middle | adds the quarter | up to 99 cents | 6 to 99 cents |
| Big | adds the dollar | up to $5.00 | 31 cents to $4.99 |
Right first time means you did not use help, did not guess a wrong total, and (on the tray) did not go over the amount. The score after ten questions is how many you got right first time. Your best score for each kind of practice and level is saved on your device. If you score 9 or 10 you are offered the next level, and the choice is yours.
Coins. Each coin is drawn with a value and a name and nothing else, in true relative sizes: the dime is the smallest and the quarter the largest. The copper one is the penny, the silver ones are the nickel, dime and quarter, and the dollar is a plain green rectangle. The coin key at the bottom lists all five. Colour is never the only clue, because every coin says what it is, and the names are never smaller than 9 pixels. The level menu and every button other than the coins themselves are at least 44 pixels tall.
Keyboard and screen readers. Everything works with Tab and Enter or Space. Each coin button says what it adds or takes off, the coins in a count question are described in words, and every step is announced in a message line under the question.
All money is a whole number of cents. A quarter is 25, a dollar is 100, and $1.35 is 135. Because nothing is ever a decimal fraction, sums are exact: the classic problem where 0.1 plus 0.2 is not quite 0.3 cannot happen. The page turns a number into text such as 35 cents or $1.35 only at the moment it shows it. The tests check formatting against a second, independent formatter for every amount from 0 to 2000 cents, and check that typed amounts round-trip with the formatter for every amount from 1 to 5000 cents.
A typed amount is read with strict rules. “35”, “35c”, “35 cents” and “35¢” mean cents. “$1”, “$1.35”, “1.35” and “$.50” mean dollars. A third decimal place, a minus sign, a comma, letters in the wrong place and anything longer than twelve characters are rejected with a hint, and the typed text is never shown back: only the number it was read as.
The fewest coins for an amount is found by dynamic programming: the best answer for each amount from 1 upward is the best answer for a smaller amount plus one coin. The change rule shown by the Show me a way button is simpler: take the biggest coin that fits, again and again. For pennies, nickels, dimes, quarters and dollars that gives the fewest coins every time, and the tests prove it by comparing the two methods for every amount from 0 to $5.00 and every level’s coin set, and against an exhaustive search for amounts up to 80 cents. The tests also show a coin set where the simple rule fails (4, 3 and 1), which is why the page only makes the claim for these five coins.
A round is built from a seed and always has ten different questions, the same ones for the same seed. Count questions use between 2 and 5 coins at Little, 3 and 7 at Middle and 4 and 9 at Big, always a total of at least 2. The four choices at Little and Middle are the answer plus three nearby totals above zero, all different. For change, the amount is always the payment minus the price, and the tests check it is above zero for every question generated.
Nothing is uploaded and there is no account. Your best score for each kind of practice and level is stored in your browser as small whole numbers under one key. Clearing site data removes it. The page address holds the practice, level and round number, so you can share a round.
For informational purposes only. Not financial, medical, or legal advice. You are solely responsible for how you use these tools.