PEMDAS is close, but not quite true.
Multiplication and Division are on the same “level”.
Addition and Subtraction are also on the same “level”.
What I mean to say is that they are the same operation.*
When it comes down to these two operations in an expression**, solve from left to right. This is something that isn’t clear by the simple “PEMDAS” acronym.
Example:
4–16/4+3*6–2*7 >(multiply and divide)> 4–4+18–14 >(add/subtract, left to right)> 0+18–14 >> 4
Now go back to 4–4+18–14 and add first, as PEMDAS suggests. Did you get -32? That answer is wrong. PEMDAS is wrong.
Likewise, here’s an analogous example, but with multiplication and division:
24/3*2
What’d you get? 4 is wrong. The correct answer is 16.
I love @LostInParadise‘s explanation of the order of operations.
*For the pedantic people: They are inverse operations, with the inverse of multiplication not being defined for r/0, where r is a non-zero real number.
**I don’t exactly know what an expression is, but I’ll say it’s a collection of numbers with operations like multiplication, addition, etc. In this quip, the bolded things are expressions.