Mentally means working out the calculations in our heads.

**Ways of multiplying mentally: **

**Commutative property:**

The commutative property of multiplication states that the order of multiplying two numbers does not change the product (a × b = b × a).

**Example:** 4 × 6 and 6 × 4

**Associative property**:

The associative property of multiplication states that the product of three or more numbers remains the same regardless of how the numbers are grouped. a × (b × c) = (a × b) × c

**For example:** 2 × (5 × 3) = (2 × 5) × 3

We can carry out the multiplication by using related multiplication facts.

**Example: 20 × 3**

To solve the above-given calculation, we can do 2 × 3 = 6

20 is 10 times larger than 2. So, the answer will also be 10 times bigger.

So, 20 × 3 = 60

**Let’s try a question:**

**Question:** Which of the following can be used to calculate 15 × 2 mentally?

**1.** 2 × 3 × 5

**2.** 15 × 2 × 1

**Explanation: **2 × 3 × 5

We know that 15 = 3 × 5

Since 15 × 2 = 2 × 15, we can say that 15 × 2 = 2 × 3 × 5

So 2 × 3 × 5 can be used to solve 15 × 2 mentally.

Leave a message