Overview
Math circle curriculum topics
Practice
Is it possible to divide the natural numbers 1, 2, ..., 20, 21 into several grou
chips are placed in a row. It is allowed to swap places of any two chips that st
Twenty years ago, banknotes in denominations of 1, 3, 5, 10 and 25 rubles were i
On 99 cards, write the numbers 1, 2, ..., 99, mix them, lay them out with their
There is a king on a certain square of the chessboard. Two people take turns mov
Ev writes one whole number on the board, and Od writes another. If the product i
Prove that if the sum of two integers is odd, then the product of these numbers
2 .The product of any two odd numbers is odd, but the sum is even. Prove it.
Numbers from 1 to 10 are written in a row. Is it possible to place “+” and “–” s
You are allowed to add one to any two numbers. Is it possible to make all number
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