Write all the factor of the following number: 21

To find all the factors of the number 21, we need to identify all the whole numbers that can divide 21 without leaving a remainder. Factors are essentially the numbers that multiply together to give the original number. Let's break this down step by step.

Identifying Factors

Factors come in pairs. For example, if we take a number and divide it by one of its factors, the result will also be a factor. For 21, we can start by checking the smallest whole numbers and see which ones divide evenly into 21.

Step-by-Step Factorization

• Start with 1: 21 ÷ 1 = 21 (So, 1 and 21 are factors)
• Next, try 2: 21 ÷ 2 does not result in a whole number.
• Then, check 3: 21 ÷ 3 = 7 (Thus, 3 and 7 are also factors)
• Continue with 4: 21 ÷ 4 does not yield a whole number.
• Check 5: 21 ÷ 5 does not yield a whole number.
• Finally, check 6: 21 ÷ 6 does not yield a whole number.

Listing All Factors

From our calculations, we can compile the complete list of factors for 21:

• 1
• 3
• 7
• 21

Understanding the Results

So, the factors of 21 are 1, 3, 7, and 21. This means that if you multiply any pair of these numbers together, you will get 21. For instance:

• 1 × 21 = 21
• 3 × 7 = 21

In summary, factors are crucial in various areas of mathematics, including simplifying fractions, finding greatest common divisors, and solving equations. Knowing how to find factors can help you in many mathematical concepts as you progress in your studies.