Regular memory method: mantissa multiplied by 2 plus 80 can quickly remember the square number. For example, the square of 5 is 25, the mantissa is 5, and the number sense memory method: remember that one kilometer is 100 m and one centimeter is 0. 1 mm, and then deduce and remember the squares of 3, 4 and 6, which can be applied after one kilometer.
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Square number or complete square number, in mathematical terms, refers to a number that can be written as the square of an integer, that is, a number whose square root is an integer. For example, 9 is a square number. Square number is also called square number. If n is a square number, you can arrange n points into a rectangle to form a square. If the concept of square number is extended to rational number, the ratio of two square numbers is still square number.
The square number other than 1 and 1 is its factor.
If an integer does not have a square other than 1 as its factor, it is called a number without a square factor. The square number is the sum of two adjacent triangles. The sum of two adjacent squares is a central square number. All odd squares are also central octagons.
2. Four squares sum theorem
The sum of squares theorem shows that all positive integers can be expressed as the sum of four squares at most. Every four consecutive natural numbers multiplied by 1 must be equal to a square number. The proposition whether there is a prime number between continuous square numbers is correct for numbers within 9000000.
3. The famous mathematician Pythagoras
Pythagoras, a famous mathematician, discovered an interesting odd number phenomenon: continuous odd numbers from 1 are added, and each gain just produces a complete square number. There is a close and important relationship between odd number and square number.
An integer is a perfect square number if and only if the same number of points can be arranged in a square grid on the plane, so that there are as many points in each row and column. The square number is the sum of two adjacent triangles. The sum of two adjacent squares is a central square number. All odd squares are also central octagons.