Remember PEMDAS?
The acronym for parentheses, exponents, multiplication/division, and addition/subtraction?
That's one of the most life saving things to learn in elementary school, with age it'll be common knowledge.
Note that multiplication/division can be treated as equals, so can addition/subtraction.
So for example if I had:
4 / 2 • 4
You wouldn't multiply the 2 and 4 first to get 8, then divide by 4 to get 2. That would be incorrect.
The correct way to solve this is to solve this from left-to-right.
So 4 / 2 = 2
And 2 • 4 = 8
Note the the first thing we did resulted in a different answer. 2 would be incorrect while 8 would be correct.
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So let's solve what's in the parentheses and brackets.
[(40 + 5) - 32]
To solve what's in the brackets we need to solve what is in the parentheses.
(40 + 5) = 45
So.. let's plug that back in to the brackets.
[45 - 32] = 13
Now let's take 13 and plug it back into our equation.
13 / 9 • 2
Let's solve this now from left-to-right.
13 / 9 = 1.4 repeating.
But since that's a decimal and we like to refrain from double rounding in math, we will take the amount you get on your calculator and immediately multiple it by 2.
1.4 repeating • 2 = 2.8 repeating.
If we were to round to the nearest tenth, our answer would be 2.9.
I hope this helps! If you have any questions, please let me know! :)