What is the product of -4 and 8.1?

a) -32.4
b) -12.1
c)12.1
b) 32.4

Option A

The product of -4 and 8.1 is -32.4

Solution:

When we multiply a negative number with a positive number we get the resultant product as a negative number.

Here we have to multiply - 4 which is a negative number and 8.1 which is a positive number.

To simplify the multiplication calculation we can write 8.1 as 8+0.1 and then multiply 4 with both 8 and 0.1

-4 8.1 = -4 (8+0.1)

⇒  -4 8.1 = -4 8 – 4 0.1  [Multiplying 4 with 8 and 0.1]

⇒  -4 8.1= -32 - 0.4

⇒  -4 8.1= - 32.4

Thus the product of -4 and 8.1 is -32.4