Onmatu- Pre-Algebra Article

Order of operations-lesson


Why do we get confused when we have many operations inside of one expression we need to manipulate?  Usually, we make mistakes when we start to calculate expressions like:

3+5×6, 2-5×3, 8+4÷2 and so on.

For the first expression, we get value 48 because we wrongly calculate it as:
3+5×6=8×6=48

we just go from left to right.  But, we need to be careful here!!!

Operations have their order, and it is:

1. × and ÷,
2. + and -.

This means that we first do multiplication and division and after addition and subtraction.  So, correct calculation of our expression 3+5×6 is:

3+5×6=3+30=33.

Similarly, we get that:

2-5×3=2-15=-13,
8+4÷2=8+2=10.

Hope this lesson helps. If not, feel free to write comments.

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