Table of Contents

- 1 How many 3 digit numbers can be formed using the digits?
- 2 How many 3 digit numbers that can be formed by using the digits 3 7 9 if the repetition of digits is allowed write all the possible numbers?
- 3 How many 3 digit numbers can be formed from the digits 2 3 5 6 7 and 9 which are divisible by 5 and none of the digits are repeated?
- 4 What are the rules for using significant figures?
- 5 How many three digit numbers are there in the world?
- 6 How many significant digits are there in the world?

## How many 3 digit numbers can be formed using the digits?

Therefore, a total of 100 3 digit numbers can be formed using the digits 0, 1, 3, 5, 7 when repetition is allowed.

### How many 3 digit numbers that can be formed by using the digits 3 7 9 if the repetition of digits is allowed write all the possible numbers?

Answer: All possible two-digit numbers formed by using the digits 3, 7, and 9 if repetition of the digit is allowed are 33, 37, 39, 73, 77, 79, 93, 97, and 99.

#### How many 3 digit numbers can be formed from the digits 2 3 5 6 7 and 9 which are divisible by 5 and none of the digits are repeated?

There is 5 possible ways to fill ten’s place. There is 4 possible ways to fill hundredth place as digits cannot be repeated. ∴ 3 – digit numbers can be formed from the digits 2, 3, 5, 6, 7 and 9 is 20.

**How many 3 digit numbers can be formed from the digits 1 2 3 4 and 5 if the digits are unique?**

Since repetition of digits is not allowed we are left with 5 digits to fill up the Tens place. So Tens place can be filled up in 5 ways. Using the same argument we can fill up the Units digit in 4 ways. Hence we can form (6)(5)(4) = 120 numbers of three digits using the digits 1,2,3,4,5,6 without repetition.

**How are three digit numbers formed in math?**

In the same way, we can define three digit numbers as those which have digits in three place values – Units, Tens and Hundreds. These are also formed by combining any three single digit numbers. Look at the simulation below to see how a 3-digit number is formed from the largest 2-digit number.

## What are the rules for using significant figures?

Rules for Using Significant Figures. For addition and subtraction, the answer should have the same number of decimal places as the term with the fewest decimal places. For multiplication and division, the answer should have the same number of significant figures as the term with the fewest number of significant figures.

### How many three digit numbers are there in the world?

There is a possibility of 10 digits in the hundredth place and 10 digits in the unit’s place. Thus, there are 9 × 10 × 10 = 900 three-digit numbers in all. Therefore there are 900 three-digit numbers in all. Example 2: A teacher wrote a puzzle on the board.

#### How many significant digits are there in the world?

All non-zero number values are significant. It is a very simple rule that all numbers from 1-9 are considered significant digits. in the above example, there are 11 digits but have only 9 significant numbers.