Parentheses in advanced Order of Operations: Decimal numbers

First, calculate the expression inside the parentheses: $3 + 1$ equals $4$.

Then multiply $0.4$ by $4$ to get $1.6$.

According to the order of operations, we will first solve the expression in parentheses.

We will solve the exercise vertically, making sure to align digits properly - ones under ones, tens under tens, and so on. Note that the decimal point is in place:

$1.4\\-0.3\\$

And we get the result:

$1.1$

Now we have the expression:

$1.1\times10=$$$

The above expression doesn't need to be calculated, we simply need to move the decimal point one place to the right, since we are multiplying by ten, meaning we're adding a tens place.

Therefore, we get the result:

$11$

According to the order of operations, we will first solve the multiplication exercises in parentheses:

$(13\times2)=26$

$(12\times1.5)=18$

Now we will subtract:

$26-18=8$