## Aplusclick Best Puzzles 2019

December 1, 2019 Leave a comment

These are the Best Puzzles published at www.aplusclick.org in 2019.

Math and Logic Puzzles

December 1, 2019 Leave a comment

These are the Best Puzzles published at www.aplusclick.org in 2019.

August 20, 2019 Leave a comment

It is the first day of a new school year, and this class has only 10 students. Ashley has 9 friends, Betty has 8, Caleb has 7, Derek has 6, Elaine has 5, Graham has 4, Henri has 3, Ivana has 2, Julie has 1. Name one of Fred’s friends.

In a group of 4 school children, each child has exactly two friends, just one of which is their best friend. What is the minimum possible number of children for whom their best friend is also that friend’s best friend?

It is the first day of a new school year, and this class has only 10 students. Ashley has 9 friends, Betty has 8, Caleb has 7, Derek has 6, Elaine has 5, Graham has 4, Henri has 3, Ivana has 2, Julie has 1. How many friends does Fred have?

It is the first day of a new school year, and this class has only 5 students. Amy has no friends yet. Betty has one friend. Chris has three friends. Derek has two friends. How many friends does Ellie have?

In a group of five students, Ann has one real friend among them, Betty has two, Craig has three, and Dianna has two. How many real friends does Edgar have in the group?

July 12, 2019 Leave a comment

How to choose the shortest road that connects several towns. This is a story about local and global minimums. Excellent presentation of soapy films.

May 27, 2019 Leave a comment

Leslie Green explains how our voting systems can be unrepresentative.

Five different parties are standing in an election for one representative. The voting methods: First past the post (FPTP): the party with the highest vote-count wins.

Is the voting system representative?

The no-pets party has 30% of the total, whereas parties that want pets are the remaining 70%. As it stands the FPTP system would vote-in the no-pets party, which does not represent the view of the electorate. What has happened is that the pro-pet movement has splintered, dividing the vote. In order to overcome this, one can use a transferable vote scheme so people can vote for their preferred option safely, preventing the hated no-pets party from winning.

A more detailed analysis can be found in an example.

March 19, 2019 Leave a comment

**Karen Uhlenbeck **to win the most prestigious award in mathematics – the Abel Prize.

The Norwegian Academy of Science and Letters has decided to award the Abel Prize for 2019 to **Karen Keskulla Uhlenbeck** of the University of Texas at Austin, USA.

Her theories have revolutionized our understanding of minimal surfaces, such as those formed by *soap bubbles*.

**Niels Henrik Abel** (1802–1829) was a Norwegian mathematician. In spite of his short life, he made significant contributions to a variety of mathematical fields.

January 2, 2019 Leave a comment

Big Ben is the nickname for the Great Bell of the clock at the north end of the Palace of Westminster in London, United Kingdom.

A pile of old coins helps to keep the clock mechanism accurate. The pennies are stacked on the pendulum of the clock and have acted as weights. Adding or taking away coins effects the pendulum’s centre of mass and the rate at which it swings. A single penny will change the clock’s speed by two fifths of one second per day.

How does the weekly time change if we add 5 pennies to the pendulum?

At twelve o’clock, twelve chimes ring from the great bell in 44 seconds. ## How long does it takes to ring the hours at 15:00 ?

November 4, 2018 Leave a comment

**Singapore math** is a teaching method based on the national mathematics curriculum used for kindergarten through sixth grade in Singapore. Singapore math, also known as the “mastery approach”: students learn a specific concept in a linear progression before moving to the next more complex subject. Students learn and master fewer mathematical concepts at greater detail using a three-step learning process: concrete, pictorial, and abstract. These are techniques of the teaching methods: to cover fewer topics in greater depth, handling objects such as pencils, dice, or paper clips, pictorial visualisation by drawing diagrams, bar modelling (a pictorial method used to solve arithmetic problems). Bar modelling is far more efficient than the “guess-and-check” approach. A 2015 study of 140 schools in the UK by found that the mastery approach improved the speed at which students learned math skills.

This is how Jeff Bezos, the richest man on the planet teaches maths to his children.