F.1 Maths

2007-09-24 3:19 am

find the value of the expression
1 - 2 + 3 - 4 + ..... +99 -100

HELP!! Plz give me the working and answer

回答 (4)

2007-09-24 3:25 am

✔ 最佳答案

1 - 2 + 3 - 4 + ..... +99 -100
= (1 – 2) + (3 – 4) + (5 – 6) + … + (99 – 100)
= (-1) + (-1) + (-1) + … (-1) [a total of 50 items]
= -50

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2007-09-24 3:34 am

(-1)x50
=-50

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2007-09-24 3:25 am

(1-2)+(3-4)+......+(99-100)
=-1x50
=-50

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2007-09-24 3:23 am

-1x(100/20)

=-50

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