What’s the Point?
In the real world, all problems start out as word problems that have to be translated in algebra to solve them using math. To get the correct answer if you have an expression with several operations, you have to do them in the standard order.
This is it: the order to do the operations in.
P – Parenthesized blocks first – Evaluate stuff inside parenthesis
E – Exponents next
MD – Multiplication and Division next. Do these in left to right order.
AD – Addition Subtraction last. Do these in left to right order.
In this example, there are two boxes, each with a group of 3 oranges, and then two oranges are eaten. The blue oranges are the ones being eaten, they are negative oranges.
A) As always the first step is to translate the problem into a mathematical expression. Here there are two identical boxes each with 3 oranges, so it makes sense to represent them as a single value, 3, times 2. Then there are the two eaten oranges. I just set them up as two -1 terms.
2*3 – 1 – 1
B) Now simplify it. To do that, remember that PEDMAS reminds you of what order to do the operations in an expression. In this case, tthe expression has a multiply and two subtractions. In PEDMAS, M means multiply and S means subtract, and the M comes before the S, so do the multiply first.
2*3 – 1 – 1 = 6 – 1 – 1
Now do the subtractions, left to right.
6 – 1 – 1 = 5 – 1 = 4
Khan has lots more!