Adding, Subtracting, Multiplying and Dividing are called operators. Operators perform actions on numbers.
There are other operators, such as indices - these control operations such as squaring a number, or finding a square root.
Brackets ( ) are used to control the order in which calculations take place.
Each operation has a priority and control the sequence in which calculations are carried out:
• Brackets are always calculated first;
• Indices - such as 32 - are calculated next;
• Divide - is next;
• Multipy (actually has the same priority as Division);
• Add - is then next;
• Subtract - (same priority as Addition).
This is known as BIDMAS (taking the first letter of each operation); sometimes it is also known as BODMAS.
When there is a mixture of operations in a calculation, the sequence of operations must be carried out in BIDMAS order.
Ellie has calculated 4 + 6 ÷ 2 = 5. Is she correct?
BIDMAS rules. The division has a higher priority than the addition and must be carried out first: 6 ÷ 2 = 3.
Then carry out the addition 4 + 3 = 7.
Put in brackets to make this calculation correct: 3 + 42 = 49
Put brackets before the 3, and between the 4 and 2.
The brackets make sure the addition is carried out first.
Answer: (3 + 4)2 = 49