Maths Topic 05 - Understanding the use of BODMAS

BODMAS or BIDMAS is a maths skill that is commonly tested in 11+ exams and Selective School exams in the UK.

Examples

Example Question 1:

7 + 6 x 5 – 1 = ?

Answer: 36

Explanation: When BODMAS is applied, the multiplication 6 x 5 is completed first and then you can start at the beginning of the sum.

7 + 30 – 1 = 36

Example Question 2:

23 – (27 – 8) + 6 = ?

Answer: 10

Explanation: When BODMAS is applied, the sum in the brackets is calculated first (27 – 8) = 19 and then you can start at the beginning of the sum.

23 – 19 + 6 = 10

Example Question 3:

87 – (4² – 5) + √9 = ?

Answer: 79

Explanation: When BODMAS is applied, the sum in the brackets is calculated first (4² – 5) → 16 – 5 = 11 as the 4² = 4 x 4. Next you should calculate the value of √9 = 3 (the square root). Then you can start at the beginning of the sum.

87 – 11 + 3 = 79

Example Question 4:

(3³ + √25) + 3(8 + 3) – 9 = ?

Answer: 56

Explanation: When BODMAS is applied, the sums in the brackets are calculated first. In the first bracket there is a cubed number 3³ = 27 and the square root √25 = 5, so 27 + 5 = 32. In the second bracket (8 + 3) = 11 and there is a 3 in front of the brackets which means that the value in the brackets (11) should be multiplied by 3 = 33. Then you can start at the beginning of the sum.

32 + 33 – 9 = 56