BODMAS rules

One consequence of combining operations in an arithmetic expression is that ambiguity may arise in expressing the outcome. In such cases, it is imperative to include brackets (the generic term), where appropriate, to indicate which arithmetic operations should be evaluated first. The order in which arithmetic operations may be combined is described, by convention, by the BODMAS rules of precedence. These state that the order of preference is as follows ... 

If we wish to evaluate 2x3 + 5, the result depends upon whether we perform the addition prior to multiplication or vice versa. The BODMAS rules tell us that multiplication takes precedence over addition and so the result should be 6 + 5 = 11 and not 2x8 = 16. Using parentheses in this case removes any ambiguity, as we would then write the expression as (2x3) + 5. 

Worked Problem 1.2 and Problem 1.4 further illustrate how the (BODMAS) rules of precedence operate. 

The BODMAS rules indicate that multiplication is performed before addition and subtraction, so evaluating gives... 

Remember that the BODMAS rules indicate that the expression in brackets is evaluated first. This is X x X -P y X y, where the multiplications are performed first. Hence... 

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