A+Click SMS Part 4

SMS stands for Short Math Situation. The SMS questions are limited to 64 characters.

91. How many 5-digit passwords are the same backwards as forwards? Answer

92. Which digit do I use less if I number 999 pages? Answer

93. How many digits are there in the result of 1001 power 11? Answer

94. How many are there symmetrical capital letters of the alphabet?  Answer

95. Four cowboys fired once. What is probability that all are dead? Answer

96. What is the largest sum of two integers which product is 787? Answer

97. The time left today is half of the time passed. What’s time now? Answer

98. How many trials are needed to identify 3 keys for 3 keyholes? Answer

99. How many 2-digit integers have the sum of the digits equals 10? Answer

100. How much paper is needed to entirely cover a 40x30x12 box? Answer

101. How many apples were sold if 33, or 11% of the total, are left. Answer

102. What area does a line cover? It is 0.25 mm thick and 8 km long. Answer

103. 3 apples weigh in pairs 200, 204, and 208. Find their weights. Answer

104. What is the angle between the hour and minute hands at 14:20? Answer

105. How many small pieces of cheese you can get using only 5 cuts? Answer

106. How many Ancient Olympic Games were held from 776 BC to 393 AD? Answer

107. How much ribbon do you need to wrap around a 12x30x40 box? Answer

108. How many 7-digit phone numbers are there?  Answer

109. Estimate the height of a lighthouse from which I can see 11km. Answer

110. Which days of the week occurred more frequently in 2012? Answer

111. 33 years, 33 months, 33 weeks, 33 days,  33 hours. How old am I? Answer

112. What is the smallest 5 digit integer with 5 different digits? Answer

The full collection of 100 SMS can be found at A+Click SMS.

What motivates us to work hard?

ImageMotivation theories can be very complex. This story is simpler than the reward analysis given in Dan Pink’s TED talk. Let’s look at a simple model of individual motivation at work, which can be presented as a MMM model:

  • M1: Myself:  I do it my way.
  • M2: Mastering:  I always improve what I do.
  • M3: Mission: I do it for a compelling purpose.

M1: Myself

Whatever I do I try to do it my way. This is valid for children and adults. We are all the same. It’s valid for work, leisure, and study. People often distress about purposelessness of their work. Doing own way is the first motivation factor for people who don’t find a potential at their main job and develop open source products like UNIX or Moodle.

M2 Mastering

Once we successfully produce something in our own manner, we constantly introduce improvements. We master our art and become craftsmen. The term ‘craftsman’ is not only related to “a skilled manual worker who makes items,“ it’s also related to teachers, software engineers, and all other professionals. It takes time to become a craftsman.

M3 Mission

A craftsman never ceases striving to master his arts, continuing to work for a purpose. In the book Craftsman, Richard Sennet said: “the craftsman is special because he or she is an engaged human being”. This stage corresponds to the highest level of the Maslow’s hierarchy of needs. Human beings are “social beings” who work together and learn by looking at how others work. Thus, we create our masterpieces for others. The purpose of creating and giving to others is at the top of the motivation pyramid.

Here is an example:

When I was a young boy, I studied mathematics in school and also on my own using Martin Gardner’s puzzles books. I often walked several miles to the city library in chilly Siberian frost to read just a few of the puzzle books’ pages. Very soon, I missed compelling challenges.

Now, as an adult, I am eager to help children throughout the world who are in the same position that I was in as a child to discover interesting, practical, and challenging math and logic puzzles and answers. We created a collection of more than 2200 compelling problems at http://www.aplusclick.com.

How the project was developed?

M1  Myself

At the beginning it was just a desire to challenge myself with logic puzzles and to present them in Internet. I saw many collections. What dissatisfied me? Existing solutions were concentrated on a specific type of problems and user age. Many of them were boring. It was difficult to fast find what I looked for. I do it in MY OWN way. I decide to improve our users’ experience according to the KISS approach: Keep It Simple and Stupid. These puzzles are illustrated, short, simple, and interesting for all ages. No sign up, no fees, and no advertising. Steve Jobs’ obsession with the customer’s experience was an inspiration for me.

M2 Mastering

After first months of exposing the set of problems, we receive feedback, suggestions for improving. It motivates us to improve the quality, to add interesting illustrations. We started to MASTERING our craft. So the number of puzzles grows to 2200 in two years and the new puzzles became more interesting.

M3 Mission

Now we continue working for a compelling PURPOSE. I always say WE, because dozens of people worldwide have helped us develop this library of math and logic problems. They thoroughly reviewed the problems and helped to make them simple and clear. Here a testimonial is:

“Strangers reaching out to one another, across great distances, just because of common interests in learning and helping other learners ~ kind mutual exchanges like this give me hope for a better world!”

Everyday, thousands of children spend a great deal of time and effort mastering their logical reasoning and mathematical thinking at Aplusclick. We thank all of our users and contributors for such a marvelous initiative to help children grow intellectually and become problems solvers.


We often find ourselves on one of the steps of the MMM model. The higher the step, the higher the level of individual motivation. More detailed hierarchy of work motivation is given in the Work Motivation pyramid. KokcharovWorkMotivation2015