Question

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

Answer 1

Step-by-step 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 $\frac{9}{10} -(\frac{6}{10})(\frac{2}{10})$

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

$\frac{9}{10} -\frac{6*2}{10*10}$

Which then becomes

$\frac{9}{10} -\frac{12}{100}$

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

$\frac{90}{100}-\frac{12}{100}=\frac{78}{100} =0.78$

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.