Mental Arithmetic Pays, Literally

You can barely see a newspaper these days without having their mental calculation skills questioned. Under the guise of "mental gymnastics" to "mathematical challenge" or similar, we are presented with a series of additions to perform.

Depending on the choice of the newspaper, they can be quite easy or even impossible to realize in his head. However, there are times when math pays, or at least be able to approximate the totals.

In the supermarket today I bought six items, and the project seemed too high at £ 15.49 for them. On leaving the supermarket double checked and realized that was £ very high as they were charged twice by a battery, when I had purchased a single 2.88.

So the mental calculation, or at least approximate what the total would be in my head, I saved £ 2.88. These are the prices of what we actually purchased - what would your approach of all these as they were out there?

Magazine: £ 3.25; Battery: £ 2.88, greeting card: £ 1. 49, chocolate pastry £ 3.66,: Book £ 0.89,: 0.60 pounds

Maths Challenge Puzzle

Maths related puzzles can provide a simple and focussed challenge - performing mental arithmetic as quickly as you can without making mistakes can actually be quite good fun!

Here are three maths challenge puzzles for you, an easy, a moderate and a hard puzzle. See if you can do them within a minute. The level of these is very fair with only a gentle increase in difficulty at each stage, so none of the calculations expected are unreasonable such as calculating 37.5% of a number or squaring 34! If you want harder ones, let me know.

Sudoku variants: smileydoku

Here is a puzzle to cheer up the first day back after the bank holiday here in the UK… a smileydoku!

The rules are as per standard sudoku, except that there are three additional regions. These are marked in grey and contain nine cells, and each must contain the numbers from 1 - 9 exactly once only. So the smile is not just symbolic here - it demarcates three additional regions of the puzzle.

See how long it takes you, hopefully once finished you will still be smiling rather than frowning! It is not too difficult, but you will need to use the additional regions to help you solve the puzzle.

Lateral Thinking Puzzle

Once upon a time, not so very long ago, there was a street swindler named Shady.

Shady used to offer everyone that walked past the chance to win a priceless diamond, but only if they could guess which hand it was in. In the other hand, was a coin, choose the coin, and lose, he used to say. And everyone did lose. To add to the drama, Shady would open the chosen hand palm down over a ‘try again’ container which the unlucky loser would, each time, see the worthless coin, and their hopes of fortune, drop into.

His stand on the street was very tempting, as it was surrounded by treasure chests full of precious stones, or at least precious looking, which tempted in the eager and occasionally greedy punter who thought they could take on Shady. Only they always lost, and went away empty handed, greasing Shady’s hand with a pound coin every time. No-one took the hint from his name that Shady was less than honest, and in fact, everytime he used a little magical flair to switch the diamond for another coin, so in fact he always had two coins in his hand.

Today Our Hero walked up to the stand (call him Fred), and did what no-one else had done - won! How did he win without having to show in any way that Shady was using underhand tactics to win?