Math Is Fun Forum

glenberg

Member

Registered: 2009-04-01

Posts: 8

is this corect

Last edited by glenberg (2009-04-04 13:52:28)

MathsIsFun

Administrator

Registered: 2005-01-21

Posts: 7,711

Re: is this corect

No.

33*10 became 3*10 (mistake?)

And -0.75+0.25 = -0.5, not -1

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"The physicists defer only to mathematicians, and the mathematicians defer only to God ..."  - Leon M. Lederman

glenberg

Member

Registered: 2009-04-01

Posts: 8

Re: is this corect

Please explain why .75+.25 become 0.5

MathsIsFun

Administrator

Registered: 2005-01-21

Posts: 7,711

Re: is this corect

OK. It was -0.75+0.25, which is "minus 0.75 plus 0.25" ... in other words "subtract 0.75, then add 0.25".

If you had 30 pizzas, and i took away 0.75 of a pizze, you would have 29.25 pizzas, if I then added 0.25 you would have 29.5.

So 30-0.75+0.25 = 29.5

BUT if I had seen () used like this: 30-(0.75+0.25) that would mean to add 0.75 and 0.25 to make 1, THEN subtract.

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"The physicists defer only to mathematicians, and the mathematicians defer only to God ..."  - Leon M. Lederman

glenberg

Member

Registered: 2009-04-01

Posts: 8

Re: is this corect

OK I understand if you if add a negative the is larger than a positive  you get a negative result.
Can we refer to the post 30X10-(1/4+1/2)+1/4 was there anything that made that -0.75 asking in case i missed something

Jai Ganesh

Administrator

Registered: 2005-06-28

Posts: 46,310

Re: is this corect

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