## BODMAS, BOMDAS, PEMDAS

Here we clarify the BODMAS rules – Do you vaguely remember hearing the acronym BODMAS from school days?   BOMDAS and in the US PEMDAS are also terms Bodmas is known as. It sets out the order of Mathematical Operations. What you may ask are Mathematical Operations? The simplest mathematical operations involve the operators    –   x   ÷   ie plus, minus, multiply and divide. These operators you are familiar with for doing simple arithmetic.

With a simple sum that only has two numbers and one single operator, it is easy to calculate the answer. Sometimes however there may be several numbers and different operations. So what do you do if in one sum you have to multiply, add, subtract and divide? There are simple BODMAS rules to follow to help you work out the order in which to do the calculations.

Brackets (any part contained in brackets comes first)

Order (operations containing powers or indices such as squaring or square rooting)

Division and Multiplication

## 7 –  1  x  0 +  3  ÷ 3  = ?

With this in mind in 2012 Dr Peter Price, the co-founder of the Classroom Professor website, posted a mathematical problem on his facebook page. Consequently seventy thousand people saw the post with 6,000 leaving answers and comments. However after 2 weeks, the results were studied and only 26% had the correct answer. The answer is 8. Most people who posted an answer would have been fairly confident of their answer so as not to look foolish on a web site. So this appears to demonstrate that the large majority of the population (probably much more than 74%) do not understand the concept of the order of operations.

Fortunately this is where BODMAS rules comes in.

In the sum 7 x 3 + 5 there are three numbers and two operators a multiplication (x) and an addition (+).

If you multiply seven by three and add five the answer is 26.

If you multiply seven x (three plus five), the answer is 56. So which is correct?

BODMAS, On the positive side there is a defined order.

## Applying the order of operations – BODMAS rules

#### Step 1:  Brackets

Firstly, the highest level order is defined by anything in brackets. Consequently these are always calculated first. If there is more than one set of brackets start at the innermost set and work outwards and you should be left with one number.

### Step 2: Order or Index

Relating to squaring or square rooting.

### Steps 3 and 4:  Divide and Multiply

Thirdly division and multiplication have equal weight and and if there is more than one operators the calculation is carried out right to left.

Therefore working from left to right 18 ÷ 6 x 4 ÷ 8. Eighteen divided by 6 is three and three times four is twelve, divided by 8 is 1.5.

### Steps 5 and 6: Add and Subtract

Again these carry equal weight so The sum is carried out right to left.

## 5 – 3 x 0 + 30 ÷ 5 = ?

The answer is at the end of the blog.

Our Letters and Numbers app uses BODMAS. Your challenge is to arrive at the target answer provided by using a set of numbers and operators and brackets.

## BODMAS Brilliance

However there was one problem where the first 200 people could not even get close. The number was 813 and the numbers were 100, 75, 50, 25, 3 and 1.   The answer to the second sum is 11.

## 3 thoughts on “How does Bodmas make a difference?”

1. Good to revise things we learnt so long ago!

2. Hello. Thx!