2.8.1 Try some yourself
Activity 9
What do the following mean?
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(a) (5 + 8)/(4 − 2)
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(b) 5 + 8/4 − 2
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(c) (4 + 5)(5 − 2)
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(d)
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(e)
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(f)
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(g) (12 − 9)−1
Answer
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(a) Add 5 and 8, and then divide the result by the difference between 4 and 2. (This gives
.) -
(b) Add 5 to the division 8/4, and then subtract 2. (This gives 5.)
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(c) Multiply the sum of 4 and 5 by the difference between 5 and 2. (This gives 27.)
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(d) Multiply 9 by the square root of 4. (This gives 18.)
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(e) Multiply 5 by 6, and then divide by 2. (This gives 15.)
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(f) The cube of the square root of 25. (That is, 125.)
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(g) The reciprocal of 12 minus 9. (That is,
)
Activity 10
What do these symbols mean?
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(a) =
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(b) <
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(c) >
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(d)
Answer
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(a) = means ‘equals’ or ‘equal to’ or ‘which equals’.
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(b) < means ‘less than’ or ‘which is less than’.
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(c) > means ‘greater than’ or ‘which is greater than’.
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(d)
means ‘is approximately equal to’.
Activity 11
What do the following mean?
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(a) mass ≥ 10 kg
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(b) time < 2.4 × 106 h
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(c) 2/3 ≠ 0.67
Answer
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(a) The mass is greater than or equal to 10 kg.
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(b) The time is less than 2.4 million hours.
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(c) Two-thirds (or 2 divided by 3) is not equal to 0.67.
OpenLearn - Language, notation and formulas
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