Order of Operations (BIDMAS/BODMAS) (WJEC Eduqas GCSE Maths: Foundation): Revision Note

Exam code: C300

Order of operations (BIDMAS/BODMAS)

What is the order of operations (BIDMAS/BODMAS)?

  • If there is more than one operation in a calculation then they should be done in the following order

    • Brackets: ( )

      • Perform any calculation(s) inside brackets first

    • Powers or Indices (sometimes Order):  2, 3, √ and similar

      • These include powers, roots, reciprocals

    • Divisions or Multiplications: × or ÷

      • If there are more than one of these then work them out left to right

      • Division includes fractions

    • Additions or Subtractions: + or -

      • If there are more than one of these then work them out left to right

  • The acronym BIDMAS or BODMAS can help you remember the order of operations

In what order should fractions and roots be dealt with?

  • Fractions mean division in calculations (BIDMAS/BODMAS)

  • There may be "invisible brackets" around the numerator and around the denominator

    • e.g.  2+57−2 means (2+5)÷(7−2)

    • Instead of brackets we extend the fraction line to show exactly what is on the top and what is on the bottom

  • Roots are powers (BIDMAS/BODMAS)

  • There may be "invisible brackets" under the root

    • e.g.  9+16 means (9+16)

    • Instead of brackets we extend the top line on the root symbol to show everything that is to be rooted

How do I use a calculator for BIDMAS/BODMAS questions?

  • Ensure that you enter a long or complicated calculation carefully

    • For most modern calculators, the calculation can be typed in exactly as it is written on paper 

    • You may need to use additional brackets on older calculators

Examiner Tips and Tricks

Make sure that you always check that your answer seems sensible!

Worked Example

Work out (5 – 3) + 2 × 72.

Answer:

Use BODMAS

First calculate anything inside brackets, 5−3=2, so the question becomes      

2 + 2 × 72

Then any powers, 72=49                

2 + 2 × 49

followed by any divisions and multiplications, 2×49=98

2+98

and finally any additions and subtractions, 2+98=100

(5 – 3)+2×72=100

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