Question

find product
(-21) x (-30)​

Answer 1

630

The value of (- 21) × (- 30) is 630.

Given data:

Two numbers (- 21) and (- 30)

To find:

Their product

Concept:

Before we solve the problem, let us know multiplication rules for signs (+, -):

1. (+) × (+) = (+)
2. (+) × (-) = (-)
3. (-) × (+) = (-)
4. (-) × (-) = (+)

Step-by-step explanation:

Now, (- 21) × (- 30)

• Hint. First we find the product of the signs. Here, the first number bears negative sign and the same for the second number. So, (-) × (-) = (+).

= 21 × 30

= 630

NOTE:

21 × 30

= (20 + 1) × 30

= 20 × 30 + 1 × 30

= 600 + 30

= 630

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