Question

I know the answer is .78, but don’t understand why? .9-.6X.2

Answer 1

Explanation:

When you multiply 0.6 and 0.2, you do not get 1.2. Rather, the product would be 0.12.

We have the equation
`0.9-(0.6)(0.2)`

To show you what is happening, lets convert these numbers into fractions

This would give us
`(9)/(10) -((6)/(10))((2)/(10))`

Recall that when you multiply two fractions, you multiply the numerators and denominators separately. Doing so gives us

`(9)/(10) -(6*2)/(10*10)`

Which then becomes

`(9)/(10) -(12)/(100)`

The last thing we need to do is to create a common denominator

`(90)/(100)-(12)/(100)=(78)/(100) =0.78`

Another way to see what is happening is by thinking about the numbers in scientific notation. Doing so would give us

`9*10^(-1)-(6*10^(-1))(2*10^(-1))`

Once we multiply these terms, we get

`9*10^(-1)-6*10^(-1)*2*10^(-1)\\\\9*10^(-1)-12*10^(-2)`

Now we can convert these numbers into decimals to get

`0.9-0.12=0.78`

Answer 2

0.6 x 0.2 = 12 and .9 - .12 = .78

It may be confusing because the decimals aren’t like whole numbers.