ATAR Notes: Forum

General Discussion => General Discussion Boards => Rants and Debate => Topic started by: EEEEEEP on November 04, 2018, 09:02:51 pm

Title: What is 80/5(7-5)? 8 or 32
Post by: EEEEEEP on November 04, 2018, 09:02:51 pm
My cousin asked me this question and I thought it was simple... on second thought it isn’t as simple as I first thought! Consulting the calculator only confused me more...

I asked a lot of people and got different answers. Some will give you the default answer of 8. Some will also say 32.

How is it 32?
(7 - 5) = 2
80/5 = 16
16 x 2 = 32

How is it 8?
80/5(7–5)
= 60/(5*2)
= 80/10
= 8.
..
(https://i.imgur.com/gi0JTkL.png)

Teachers and mathematicians (and all), what is the right answer? When I was taught in High school and primary school ( I would have gotten "8").
Some people also say that the division sign can be interpreted as a fraction....

Sidenote: This also confused me as well. My calculators are getting two different answers... HAHAH.

(https://i.imgur.com/xAhAkFO.jpg)
....

What's the correct answer here?
Title: Re: What is 80/5(7-5)? 8 or 32
Post by: fun_jirachi on November 04, 2018, 09:10:14 pm
The absence of any other brackets and any other signs indicates that the '5(7-5)' part is just multiplication. Nowhere does it indicate that the (7-5) should be divided. Since multiplication + division go left to right, you should get 32. Your working for 8 is wrong, you've added brackets out of nowhere which changes the order of operations.
Title: Re: What is 80/5(7-5)? 8 or 32
Post by: lach_chau04 on November 17, 2018, 06:10:45 pm
Should be 32. Once you do the brackets, you multiply or divide from left to right.