1, simplified method
For the square root of a number, if the single digit of this number is one of 1, 4, 5, 6, 9, then the single digit of its square root can only be one of 1, 2, 5, 6, 9. For example, the root number 16 is about 4, and the root number 25 is about 5. This method is suitable for estimating the square root of an integer.
2. Approximation method
For the square root of non-integer, we can estimate it by approximation. Find the number between two complete squares of the number first, and then take its average value as the estimated value of the number. For example, if we estimate the value of the root number 8, we can find two complete square numbers 4 and 9, and their average value is 6.5, so the root number 8 is about 6.5. This method is suitable for estimating the square root of non-integers.
3. Decomposition method
For a larger number, we can estimate its square root by decomposition. Firstly, the number is decomposed into the product of two smaller numbers, and then the root numbers of these two numbers are estimated. For example, to estimate the value of root number 80, we can decompose 80 into the product of 8 and 10, whose square roots are about 2.8 and 3.2 respectively, so the root number 80 is about 2.8 times 3.2, that is, 8.96. This method is suitable for estimating the square root of a large number.
Root number introduction:
The radical sign is one of the symbols commonly used in mathematics. It is used to represent the square root of a number. The root number (√) is usually placed in front of the number of the opened party, such as √2, √3, etc. The use of the radical sign of mathematical symbols not only concisely but also effectively expresses mathematical concepts. The radical sign is often used in mathematical expressions, especially in algebra and geometry. In algebra, we often have to solve equations, and the root sign is one of the important processes of solving equations.
At the same time, the use of the root sign often appears in trigonometric functions, such as sine function, cosine function and tangent function. In geometry, the root sign is also widely used to describe the shape and size, including calculating the area, perimeter and other issues.