Is it true that "approximate number 220 and approximate number 0.101 both have three significant numbers"?

Is it true that "approximate number 220 and approximate number 0.101 both have three significant numbers"?

yes
A number is close to the exact number, and slightly more or less than the exact number. This number is called approximate number
If an approximate number is rounded to any digit, it is said that the approximate number is accurate to any digit, from the first digit on the left which is not zero to all digits on the precise digit
It is expressed by the number of significant digits. There is an approximate number obtained by rounding, from the first non-zero digit on the left to the last digit. All digits are called the significant digits of this number

Explain the approximate number and effective number of the first day of junior high school

Rounding of approximate numbers
The significant number starts from the first non-zero number from the left to the right, followed by all the others

Judgment: 1.6 and 1.60 are equal in size, but different in accuracy ()

Right. Two numbers are the same, the more accurate the number is to the decimal point, the higher the accuracy of that number

Please prove that there are as many rational numbers as natural numbers

To prove the specific process, we need to use the knowledge of discrete mathematics, and only prompt the key step: (in the case of ignoring relatively few repetitions (such as: 2 / 1 = 4 / 2 = 6 / 3, 8 / 3 = 16 / 6, etc.), there are as many positive rational numbers as positive integers.) any positive rational number can be written as M / N (m, n are positive integers), which can be arranged as

Is 0 a rational number? Is it a natural number? What does rational number include? What does natural number include?

Rational numbers are integers and fractions. They can also be divided into positive numbers, 0 numbers and negative numbers. The definition is that real numbers other than infinite acyclic decimals are collectively called rational numbers;
Natural numbers are zero and positive integers

There is a natural number with two digits. Three times the sum of the two digits is exactly the natural number. What is the natural number?
Please use elimination method

27
Natural number = 3 * (TENS + ones) = 3 * tens + 3 * ones
Natural number = 10 * tens + ones
So 3 * tens + 3 * ones = 10 * tens + ones
2 * single digit = 7 * ten digit
Because the tens are greater than 0 and less than or equal to 9, the ones are greater than or equal to 0 and less than or equal to 9
So it can only be a ten digit number of 2 and a single digit number of 7

Write all the 100 natural numbers from 1 to 100. The sum of all the digital words used is______ ．

The sum of all the digital words used is (1 + 2 + 3 +...) +8 + 9) × 10 × 2 + 1 = 1 + 92 × 9 × 10 × 2 + 1 = 901

Three continuous natural numbers, the largest one is a, and the other two are______ 、______ ．

Three continuous natural numbers, the largest one is a, the other two numbers are A-2, A-1. So the answer is: A-2, A-1

What is natural number rational number real number set

1) The set of all non negative integers is usually referred to as the set of non negative integers (or set of natural numbers) ". 0, 1, 2, 3, 4 0 and positive integers are natural numbers
2) Rational number: a number that can be accurately expressed as the ratio of two integers. Integers and fractions are collectively called rational numbers. This fraction can also be expressed as a finite decimal or an infinite circular decimal
3) Rational numbers and irrational numbers are called real numbers
Set of real numbers: the set of all real numbers

How to prove that the potential of algebraic number set is the same as that of rational number set, and that of transcendental number set is the same as that of real number set

It should be known that the set of rational numbers is countable. Algebraic numbers are the roots of polynomials with rational coefficients. For a polynomials with rational coefficients of degree n, there are only a limited number of roots. All polynomials with rational coefficients of degree n are equal to Q ^ n, so they are countable