Number Focus Group
Order of Operations
When performing mathematical operations there is a particular order in which the operations must be done. If we fail to do things in the correct order, we may end up with the wrong answer. The order of operations is:-
2. Indices (also known as exponents or powers of) 2
3. Division and multiplication
4. Addition and subtraction
Some people remember this as BIDMAS (an acronym for the above list). This means that when looking at a calculation you should fi do the operations inside brackets, then do any indices. Then you should do any division or multiplication, working from left to right in the equation. Finally do addition and subtraction, again working from left to right in the expression. Powers should be treated as a high-priority multiplication.
Example 1 :
What is 3 + 3 × 10?
3 + 3 × 10 = 3 + 30 Using BIDMAS, we have no brackets or indices so we do the multiplication first hence.
Note: If we did not follow the correct order of operations we may have got 60 as our answer.
Example 2 : What is 3 × (7 + 2) + 6?
3 × (7 + 2) + 6 = 3 × 9 + 6 (do the bracket first)
= 27 + 6 (then do the multiplication)
Example 3 : What is 3 + 15 x 22?
3 + 15 x 22 = 3 + 15 x 4 (do the indice first, 2 x 2)
= 3 + 60 (then do the multiplication)
Note: If we did not follow the correct order of operations we may have got 72 as our answer.
Example 4 : What is 3 x 3 + 6 ÷ 3?
3 x 3 + 6 ÷ 3 = 9 + 6 ÷ 3 Do any division or multiplication, working from left to right in the expression.
= 9 + 2
Complete the worksheet 'BIDMAS CLASSWORK2" on Edmodo - you will need to join my class with the code y9cpqg
Once you have finished please save your worksheet as 'Your name BIDMAS CLASSWORK2' and 'Dropittome' using the password Dreambig135
If you finish the worksheet please begin working on the more challenging extension work labelled PEMDAS extension, also on Edmodo.
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