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The following activity is a practice exercise to help you measure your success under timed conditions. 

If you are unsure of an answer move on to the next question.  You should come back to questions you found difficult at the end if you have time.  


Look at the following calculation:

7 + 5 x 3 = 10 x 2 + ( __ )

Both sides of the calculation must be equal.

We need to work out the answer to the left side of the calculation before we can work out the mystery number on the right side of the calculation.

boy with laptop


We must follow the rules of BIDMAS (or BODMAS) in these calculations.

When you complete a calculation using BIDMAS, you answer anything in brackets first, then any indices (squared and cubed numbers),  then the division and multiplication parts, followed by the addition and subtraction parts.


Following the rules of BIDMAS, we must calculate 5 x 3 first and then add 7. This gives us 22.

So the answer on the right must equal 22. 10 x 2 is 20 so the mystery number must be 2 to make a total of 22.

7 + (5 x 3) = (10 x 2)+ 2


Now it's time to begin this practice exercise.  Good luck!





10 questions