Brainteasers

Numbers and Dots ★★★★

Puzzle

This is a famous problem from 1882, to which a prize of $1000 was awarded for the best solution. The task is to arrange the seven numbers 4, 5, 6, 7, 8, 9, and 0, and eight dots in such a way that an addition approximates the number 82 as close as possible. Each of the numbers can be used only once. The dots can be used in two ways: as decimal point and as symbol for a recurring decimal. For example, the fraction 13 can be written as

  .
. 3

The dot on top of the three denotes that this number is repeated infinitely. If a group of numbers needs to be repeated, two dots are used: one to denote the beginning of the recurring part and one to denote the end of it. For example, the fraction 17 can be written as

  .         .
. 1 4 2 8 5 7

Note that '0.5' is written as '.5'.

The question: How close can you get to the number 82?

The solution: Click here!