Tasks for children, over which adult aunts and uncles scratch their heads

The education system requires more and more efforts from students every year. Even at school, the burden on children and teachers is growing. It is not surprising that some play-off their complexity and complexity are able to stupor even adults with diplomas of reputable universities. Why is that? Is the new generation so smarter than ours?

We're in the newsroom. "Site" We are sure that modern adults do not cope well with school problems only because they have already become accustomed to solving them. Therefore, from time to time we offer readers interesting problems, the solution of which will be an excellent warm-up for the brain. And you can find a solution both alone and with children.



Challenges for children Conditions of tasks

1. As a first task, we offer the most common example. However, here too, many manage to make a mistake, because there is addition, and subtraction, and fractions. Anyone who remembers the basic mathematical rules will be able to cope.
   
   
   
   
2. For a change, the second task will be a full task. These are the kinds of tasks that cause them. math class The most interesting. After all, even not the most diligent student can find a solution due to ingenuity and the ability to think logically. And get a good grade. So, according to the terms of the problem, the son is 3 times younger than his father. Although 5 years ago he was exactly 4 times younger. Is it possible to find the current age of both father and son?
   
   
3. And finally, we offer a more difficult task, to cope with which not everyone will succeed. But it's more interesting to decide. A curious reader estimated that the publisher had to use 2,775 digits to number all the pages of his favorite book. How many pages are there in the book?
   
   
   
   
   
   

Problem-solving

1. “First division and multiplication, and then addition and subtraction” – this rule is probably heard by everyone, but not everyone remembers it until now. They make a mistake in solving such examples. But that's not all. After all, to divide a number by a fraction, you need to multiply it by an inverted fraction. Therefore, our example turns into 4 – 2 * 2 + 1 = 1. How many have found the same answer?
   
   
   
   
   
   
2. To find a solution to the problem, you can take the age of your son 5 years ago for. Then his current age will be +5. The age of the father 5 years ago is 4, and the age of the father today can be given as 4 + 5 or (+ 5) * 3. This means that 4 + 5 = ( + 5) * 3. If we open the brackets, we get 4 + 5 = 3 + 15. Where does 15 = 5 = 10? So we found the age of my son 5 years ago. So now he's 10 + 5 = 15 years old. And the current age of the father in this case is 15 * 3 = 45 years.
   
   
   
   
   
   
3. This book seems pretty thick. But we will try to solve the problem without haste. So, to number the first 9 pages you need 9 digits (one dial). Next, we will use two digits for numbering (from the tenth to the 99th page). In total, 90 * 2 + 9 = 189 digits are used to number the first 99 pages. Not enough. To number the pages from the 100th to the 999th (you get 900 pages), you need another 3 * 900 = 2700 digits. And then 2700 + 189 = 2889 digits. This is more than stated in the conditions of the problem (2775 digits). So there's less than 999 pages in the book. And less by (2889 – 2775) / 3 = 114 / 3 = 38 pages. In this case, 999-38 = 961 pages.
   
   
   
   
   
   

We hope that you enjoyed these tasks and made you think a little. Write whether you managed to cope with each task, and also share your results. Who knows, maybe we made a mistake and made a mistake.