Question

To find the product of 0.8 x 0.6, Alison used this model. Which statement explains how she most likely used this model to find the correct answer most efficiently?

Answer 1

Model used is

`(x+a)(x+b) = x^2+(a+b)x+ab`

Explanation:

To find the product of 0.8x0.6 using the known identities

We find that both numbers are near to 1.

Hence x can be taken as 1

We know that

`(x+a)(x+b) = x^2+(a+b)x+ab`

can be used here making x = 1 and a =-0.2 and b=-0.4

The product becomes
`(1-0.2)(1-0.4) </p><p>= 1^2-1(0.2+0.4)+0.2(0.4) </p><p>= 1-0.6+0.08 = 0.48`

THus we find easily using the mdoel that answer is 0.48