1. Adapted from an idea by Monica Yuskaitis
BODMAS/BIDMAS The Rule of the Order of Operations In BODMAS the O stands for Order. Sometimes this rule is called BIDMAS, where the I stands for Indices (Index number). Order and Indices mean the same thing.
Adapted from an idea by Monica Yuskaitis

2. Which is the Index Number?
Index Numbers (Indices) are little numbers high up and to the right of a base number. 3 4
Index
number
Base
Number

3. What are Index Numbers?
Index Numbers (Indices) tell us how many times a number is multiplied by itself. 3 4
Index
Number
Base
Number

4. What does an Indices mean?
The Indices tell us how many times a number is multiplied by itself. 4
= 3 x 3 x 3 x 3 3

5. How to read an Indices
This indices is read eight to the power of four. 8 4
Index
Number
Base
Number

6. How to read an Indices
This indices is read three to the power of two or three squared. 3 2
Index
Number
Base
Number

7. How to read an Indices
This Indices is read three to the power of three or three cubed. 3 3
Index
Number
Base
Number

8. Read These 3 2 6 7 2 3 5 4

9. What would the Index Number be?3
2 x 2 x 2 = 2

10. What would the Index Number be?2
3 x 3 = 3

11. What would the Index Number be?4
5 x 5 x 5 x 5 = 5

12. What are the Base and Index Numbers?4
8 x 8 x 8 x 8 = 8

13. What are the Base and Index Numbers?5
7 x 7 x 7 x 7 x 7 = 7

14. What are the Base and Index Numbers?9 2

15. How to Multiply Out Indices4 3
= 3 x 3 x 3 x 3 9 27 81

16. Calculate this 2 4 16 =

17. Calculate this 3 2 8 =

18. Calculate this 2 3 9 =

19. Calculate this 5 3
125 =

20. Indices are often used in area questions to show the units are squared
length x width = area
A pool is a rectangle
length = 30 ft
width = 15 ft
area = 30 x 15 = 450 ft
15ft
30ft 2

21. length x width x height = volume A box is a rectangle length = 10 cm
Indices are often used in volume questions to show the centimeters are cubed
length x width x height = volume
A box is a rectangle
length = 10 cm
width = 10 cm
height = 20 cm
volume =
20 x 10 x 10 = cm 20 10 10 3

22. Here are some areas What are the Indices?2
40 feet squared = 40 ft
56 sq inches = 56 in
38 m squared = 38 m
56 sq cm = 56 cm 2 2 2

23. Here are some volumes What are the Indices?3
30 cubic feet = 30 ft
26 cubic inches = 26 in
44 metres cubed = 44 m
56 cubic cm = 56 cm 3 3 3

24. Applying this to questions
Use the BODMAS rule.
Brackets first – then look for Indices.
Always calculate the indicies next.
Watch out for sneaky ones! 0.3 2

25. You will often meet this type of sum in area and volume questions.
Stick to the BODMAS rule and calculate carefully. More on this in Section 7: Formula
Have fun!