How to do the dime and penny trick

A friend hides a dime in one hand and a penny in the other. They do a quick sum in their head and tell you the total. From that number alone, you name which hand holds the dime. It is self-working: the secret is that a dime is worth an even number of cents and a penny an odd number.

What does the audience see?

You turn your back while a friend puts a dime in one hand and a penny in the other. You ask them to do a little arithmetic with the coins’ values and tell you the answer. Without seeing their hands, you tell them the dime is in their right hand, and you’re right. You can repeat it, and you’re right every time.

What do you need?

• A dime (10 cents) and a penny (1 cent). Any two coins work if one has an even value and the other an odd value.
• A friend who can multiply small numbers in their head, or a pencil and paper.

How do you do the dime and penny trick?

1. Hide the coins. Turn away and ask your friend to hold the dime in one hand and the penny in the other, without telling you which is where.
2. Multiply the right hand. Ask them to multiply the value of the coin in their right hand by 7. For the dime that is 70; for the penny, 7. They keep the answer to themselves.
3. Multiply the left hand. Ask them to multiply the value of the coin in their left hand by 6.
4. Add. Ask them to add the two answers together and tell you the total.
5. Reveal. If the total is even, the dime is in their right hand. If the total is odd, the penny is in their right hand and the dime is in their left.

Check it: with the dime in the right hand, 70 + 6 = 76, which is even. With the penny in the right hand, 7 + 60 = 67, which is odd.

Why does it work?

Any number multiplied by an even number gives an even answer, so the left hand always adds an even amount. The right hand decides everything. An even coin (the dime) times 7 stays even, so the total is even. An odd coin (the penny) times 7 stays odd, so the total is odd. Only the last digit of the total matters to you.

You can use other numbers, as long as the right-hand multiplier is odd and the left-hand multiplier is even.

Where did the dime and penny trick come from?

We can’t name an originator. Based on our research, the earliest mention we’ve found of this odd-and-even principle is in Miscellaneous Notes and Queries, January 1892, with counters held in each hand. Henry Ernest Dudeney later set it as a puzzle, “Odds and Evens”, in Modern Puzzles, using the same 7 and 6. A coin-and-hand version also appeared in The Friend magazine in January 1984, with pennies.

The name is also used for a different kind of coin magic: Lloyd E. Jones published a booklet of coin tricks with a dime and a penny, Dime and Penny, in 1945, and some of its routines use gimmicked shells. The trick in this post needs no gimmick.

How do you make it look better?

• Don’t mention odd or even. Ask only for the total. If people hear “odd or even”, they start looking for the method.
• Take a moment before the reveal. Look at their closed hands as if you’re reading them, then name the hand.
• Change the numbers when you repeat it. Use 3 and 4, or 5 and 2, so the sum looks different each time.
• Use paper for younger friends. A pencil and pad make the sums easier, and the trick still works.

What are the common mistakes?

• Mixing up the hands. The odd multiplier always goes with the right hand in your instructions. Swap them and your rule flips.
• Arithmetic slips. If your friend adds wrongly, you’ll be wrong. Keep the numbers small.
• Repeating it too often. Two or three times is plenty. Follow it with a different coin trick, such as the heads or tails prediction.

If you like number tricks, try the magic number nine trick, or see our easy mentalism collection.

What helps you take it further?

• Modern Coin Manipulation by T. Nelson Downs (1900), free from our public-domain library. It covers palms, passes, vanishes and the Miser’s Dream.
• Super Scotch and Soda (US Half Dollar and English Penny) by Tango Magic. A magnetic version of the classic Scotch and Soda gimmicked coin that needs no set-up before you perform, with a tutorial routine using cards and coins.
• Morgan Replica by Tango Magic. A finely crafted silver-colour replica Morgan coin. Find more in our replica coins collection.

Frequently asked questions