# What is bid-mass?

Its the order of what you do things in a maths calculation

B=brackets

I= indices (powers)

D=division

M=multiplication

A=addition

S=subtraction

If you calculate the '4 + 2' part first you get:

4 + 2 × 3 = 6 × 3 = 18

If you calculate the '2 × 3' part first you get:

4 + 2 × 3 = 4 + 6 = 10

These are two very different answers, but only one is correct.

In BIDMAS, multiplication comes before addition, so multiply 2 by 3 first.

4 + 2 × 3 = 4 + 6 = 10, so this is the right answer.

This sum has only addition and subtraction. So work them out from left to right.

9 - 4 + 3 = 5 + 3 = 8

Notice that if you didn't go from left to right you would get a different answer:

9 - 4 + 3 = 9 - 7 = 2

But that would be the wrong answer. Always work them out from left to right.

B=brackets

I= indices (powers)

D=division

M=multiplication

A=addition

S=subtraction

## Example

What is 4 + 2 × 3?If you calculate the '4 + 2' part first you get:

4 + 2 × 3 = 6 × 3 = 18

If you calculate the '2 × 3' part first you get:

4 + 2 × 3 = 4 + 6 = 10

These are two very different answers, but only one is correct.

In BIDMAS, multiplication comes before addition, so multiply 2 by 3 first.

4 + 2 × 3 = 4 + 6 = 10, so this is the right answer.

## Example

What is 9 - 4 + 3?This sum has only addition and subtraction. So work them out from left to right.

9 - 4 + 3 = 5 + 3 = 8

Notice that if you didn't go from left to right you would get a different answer:

9 - 4 + 3 = 9 - 7 = 2

But that would be the wrong answer. Always work them out from left to right.