536 Puzzles and Curious Problems

40 Arithmetic & Algebraic Problems

nine digits once, and once only? The fractions may be formed in one of the

following ways:

We have only found five cases, but the fifth contains a simple little trick

that may escape the reader.

134. DIGITS AND PRIMES

Using the nine digits once, and once only, can you find prime numbers
(numbers that cannot be divided, without remainder, by any number except
1 and itself) that will add up to the smallest total possible? Here is an example.
The four prime numbers contain all the nine digits once, and once only, and
add up to 450, but this total can be considerably reduced. It is quite an easy
puzzle.

61

283

47

59

450

135. A SQUARE OF DIGITS

The nine digits may be arranged in a square in many ways, so that the

numbers formed in the first row and second row will sum to the third row.

We give three examples, and it will be found that the difference between the

Z '1 3 3 Z r

(^5 4 6 6 5 4)
8 1 ~
i~ B 1