## The Best Aplusclick Puzzle 2020

January 5, 2021 Leave a comment

Here they go

Math and Logic Puzzles

April 5, 2020 Leave a comment

There are 5 counters in a bag. Three are Argentinean (blue) and two are Brazilian (green). Three counters are randomly picked out of the bag, one by one. They are not returned to the bag.

What probability is higher?

A. The probability of choosing * three Argentinean counters* in a row.

B. The probability of choosing * two Brazilian counters* in a row and then one Argentinean counter.

Find the answer.

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?

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.

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.

October 8, 2018 Leave a comment

We use math symbols to express complex mathematical texts in a shorter form.

= replaces “*is equal to*”

+ replaces “*and*”

× replaces “*multiplied by*”

. . . .

There are many Greek symbols like π ∑ and special symbols like √ ∞ ∈ in mathematics.

John David Walters explains where math symbols come from in the video:

September 8, 2018 Leave a comment

The term “Boolean algebra” honors George Boole (1815–1864), a self-educated English mathematician. Boolean algebra captures essential properties of both set operations and logic operations. Boolean logic is credited with laying the foundations for the information age (computers and cell phones).

One of the puzzles on Boolean logic:

There are three balls X, Y and Z. They are colored red, white and blue, but not necessarily in this order. One, but only one, of the following statements is true:

X is red

Y is not red

Z is not blue

How many solutions does the puzzle have?

Think yourself before checking the solution.

August 5, 2018 Leave a comment

The picture shows a subway map. A team of inspectors verifies passengers’ tickets at a station on a line, or all lines through it if there are many lines. Then they randomly choose the next neighboring station and move there to make their inspection.

How many times higher is the probability of being inspected at station C than at station A?

Are you eager to know the answer? Try yourself before reading how Markov Chain helps to solve the problem. The answer is here.

The perfect explanation is given in the PBS Infinite Series video:

February 8, 2018 Leave a comment

**e ^{iπ} + 1 = 0**

Euler’s identity is often cited as an example of deep mathematical beauty.

*Constance Reid*: Euler’s identity is “the most famous formula in all mathematics”.

Euler’s Identity is a special case of his formula from complex analysis suggested by Swiss mathematician *Euler* in 1748.

The identity links five fundamental mathematical constants:

- The number
**0** - The number
**1** - The number
**π**(**π**= 3.141 . . .) - The number
(**e**= 2.718 . . .)**e** - The number
, the imaginary unit of the complex numbers.*i*

Euler’s Identity “is absolutely paradoxical; we cannot understand it, and we don’t know what it means, but we have proved it, and therefore we know it must be the truth”. – *Benjamin Peirce*.

December 8, 2017 Leave a comment

Alan Smith reported amazing statistics of adult numeracy:

2011 England Survey: **49 of 100** adults lacked of numeracy Level 1 skills (fractions, percentage, and decimals). *The figure is only shocking for 51% of population.*

OECD reported (PIAACX2012) that **forty percent** of USA young people aged 16-19 were below Level 2.

This is statistics. Statistics is a part of mathematics and it is about **us** as a group.

There are two categories of people who can and who cannot do numbers.

Are You in a category of people who are comfortable with numbers? Check / train yourself at the website A+Click