Science is Magic

87

MATH

PART...

THE

4

To understand why this trick always works,

ask yourself these questions:

• What would happen if all the coins you turned over into
  the new pile were tails? They would all become heads and
  match the number in the original pile.


• What if all but one of the coins you turned over was tails?
  You’d have one less head in the new pile, but you also took
  a head from the original pile so there’s one less there, too!


• What if all but two turned coins were tails?

Can you see a pattern? The mathematics

at the heart of this trick means that

as long as you know how many

coins are originally face up, you

will always split the heads perfectly.

With the

blindfold still on,

remember the

number of heads

you counted

earlier. Turn over

that many coins

and put them

in their own

new pile.

5

Wow! Your prediction came true

and there’s an equal number of

heads in both piles. If your friend

thinks you were just lucky,

do it again... you will

always get it right.

C O I N M A

G IC

M A T H E M A T

IC

AL

TH

E

(^) N
U
M
B
E
R
(^) O
F H E A D S
(^) A
L
W
AY
S (^) M
ATCHE
S!
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US_086-087_Mathematical_coin_magic.indd 87 09/10/2018 10:20