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N.2 Multiply 1 by numbers up to 12

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What is the Identity Property of Multiplication?

The Identity Property of Multiplication states that any number multiplied by 1 equals that same number. The number 1 is called the "identity" because it keeps the other number's identity unchanged.

Examples:
  • 7 × 1 = 7
  • 1 × 4 = 4
  • 12 × 1 = 12
Note

Think of multiplying by 1 like looking in a mirror. You see yourself, not a changed version. The number stays exactly the same.

How Do We Multiply by 1?

To multiply any number by 1, you simply state the original number. The order does not matter: 1 × a number and a number × 1 give the same result.

Steps:
  • Look at the problem: 9 × 1
  • Ask: "What is 9 groups of 1 object?" The answer is 9 objects.
  • Write the answer: 9 × 1 = 9
Note

Always check: If one of the numbers you are multiplying is 1, your answer will be the other number.

Multiplication Facts with 1 (Up to 12)

Learning all the multiplication facts where 1 is a factor helps build speed and confidence. Here is the complete set.

Fact Family for 1:
  • 1 × 0 = 0
  • 1 × 1 = 1
  • 1 × 2 = 2    |    2 × 1 = 2
  • 1 × 3 = 3    |    3 × 1 = 3
  • 1 × 4 = 4    |    4 × 1 = 4
  • 1 × 5 = 5    |    5 × 1 = 5
  • 1 × 6 = 6    |    6 × 1 = 6
  • 1 × 7 = 7    |    7 × 1 = 7
  • 1 × 8 = 8    |    8 × 1 = 8
  • 1 × 9 = 9    |    9 × 1 = 9
  • 1 × 10 = 10   |   10 × 1 = 10
  • 1 × 11 = 11   |   11 × 1 = 11
  • 1 × 12 = 12   |   12 × 1 = 12
Note

This is the easiest fact family to learn! The pattern is simple and never changes, which makes it a great starting point for multiplication.

Using Multiplication by 1 in Word Problems

Recognizing when to multiply by 1 in real-world situations helps you understand the concept deeply.

Example Problems:
  • If there is 1 basket and it holds 5 apples, how many apples are there?
    1 × 5 = 5 apples
  • You have 8 boxes. Each box contains 1 prize. How many prizes do you have?
    8 × 1 = 8 prizes
  • A single package of markers has 12 markers. You buy 1 package. How many markers do you get?
    1 × 12 = 12 markers
Note

Look for phrases like "each one has," "a single," or "every group" when identifying the number 1 in a word problem.