Moved - dividing numbers !

[pooya]

hello

well here it is :

I've done it by an app named : algebrator for students

but my calculator shows somthing diffrent ! and so do I !

and also if I write this problem like this:

it shows me a the same answer with my calculator !

whats the problem ? why this happens ?

is it about rules of rational numbers ??

plz help me . thank you all​

 

[Deleted member 4993]

hello

well here it is :

I've done it by an app named : algebrator for students

but my calculator shows somthing diffrent ! and so do I !

and also if I write this problem like this:

it shows me a the same answer with my calculator !

whats the problem ? why this happens ?

is it about rules of rational numbers ??

plz help me . thank you all​

\(\displaystyle \dfrac{6}{2(1+2)} \)

= 6\[2*(1+2)]

= 6\[2*3]

= 6\6

= 1

 

[stapel]

Can't post this reply

well here it is:

. . . . .\(\displaystyle \large{ \dfrac{6}{2\, (1\, +\, 2)} }\)

This, written horizontally, is the same as:

. . . . .\(\displaystyle \large{ 6\, \div\, \bigg[\, 2\, (1\, +\, 2)\,\bigg] }\)

This grouping is caused by the horizontal fraction line, which forces everything past the "6" to be considered together. (Fractions, by their nature, may be viewed as having grouping symbols around their numerators and denominators.)

I've done it by an app named : algebrator for students

but my calculator shows somthing diffrent ! and so do I !

. . . . .\(\displaystyle \large{ 6\, \div\, 2\, (1\, +\, 2)\, = 6\, \div\, 2\, \times\, 3 }\)

By converting the original expression from fractional form without including the required grouping symbols, you have changed the meaning. The above, written in fractional form, would be as follows:

. . . . .\(\displaystyle \large{ \dfrac{6}{2}\, \times\, (1\, +\, 2) }\)

This is very clearly not the same expression as was originally given! :shock:

 

[ulrichburke]

What they're trying to say is Please Excuse my Dear Aunt Sally...

Dear Dividing Numbers.

In England, it's BODMAS. In America, it's Please Excuse my Dear Aunt Sally (PEMDAS). (England) Brackets Off Divide Multiply Add Subtract (America) Parentheses Multiply Divide Add Subtract.

I'm British so I prefer Bodmas! It's one of those things you CAN mathematically prove but you're better off memorizing it. What's happening with your sum is you're removing the brackets but forgetting to then multiply the answer to the sum inside the brackets by the 2, so you're not obeying Bodmas, so the answer's coming out wrong. Calculators only do what you tell them unless they're special ones, so if you do the sum in bits on a calculator you'll get your (wrong) answer because you'll have told it to do the wrong things. You have to get the BODMAS bit right yourself (you're the human!) and make sure you tell the calculator to do things in the right sequence. It's an easy thing to fall over. (I've fallen over something even dumber in a question I've posted and I'm danged if I know what it is. Yet. Of course there's gonna be 200 people telling me how dumbass I've been in no time...)

Aunt Sally would be Most Displeased with you (but please excuse her!)

Chris.