How many times does 9 occur between 1 to 100?

Explanation

Between 1 and 100, 9 occurs in units and tens places

In units place, i.e., 9, 19, 29, 39, 49, 59, 69, 79, 89, 99

9 occur 10 times

In ten's place i.e., starting from 90 to 99, (90, 91, 92, 93, 94, 95, 96, 97, 98, 99)

9 occur 10 times

∴Total = 20 times

Types Of Numbers

Whole numbers- They are part of a number system that includes all positive integers from 0 to infinity. These numbers are on the number line. So they are all real numbers. We can say that all whole numbers are real numbers, but not all real numbers are whole numbers. So we can define the whole numbers as the set of natural numbers and 0.

Natural numbers- The natural numbers are the set of all whole numbers except 0. Natural numbers are part of a number system that includes all positive numbers from 1 to infinity. Natural numbers are also called counted numbers because they do not contain zero or negative numbers. These are a subset of real numbers, containing only positive integers, but excluding zero, fractions, decimals, and negative numbers.

Integers- An integer is a series of numbers (positive and negative) counted with zero that can be written without fractions. All natural numbers are integers, starting at 1 and ending at infinity. All whole numbers are also integers, starting at 0 and ending at infinity.

Irrational numbers- Irrational numbers are those real numbers that cannot be represented in the form of a ratio. In other words, those real numbers that are not rational numbers are known as irrational numbers

Rational numbers- Rational numbers are real numbers. A rational real number is one whose decimal expansion ends after a finite number of digits (eg, 3/4 = 0.75) or ends up repeating the same finite number of digits over and over again.