Answering on question "9-3÷⅓+1"

ToonWK · March 9, 2021, 10:29am

This does look confusing and it’s been a long time got a math class properly…

So, trying my best to answer that “9-3÷⅓+1”

Well at first I would try going forward to back:

9-3÷⅓+1 = 6÷⅓+1

= ⁶∕₆÷⅓+1

=(⁶∕₆×³∕₁)+1 (Idk, my math teacher used to tell me that a fraction divide by fraction, has to flip to fraction multiply by back-flip-fraction)

=¹⁸∕₆+1

=³∕₁+1

=3+1

=4?

Now what about back to forward:

9-3÷⅓+1=9-³∕₃÷⅓

=9-(³∕₃×³∕₁)

=9-⁹∕₃

=9-³∕₁

=9-3

=6?

Well that’s different! I’m starting to doubt that neither is correct…

So here’s another potentially wrong one:

9-3÷⅓+1=9-(3÷⅓)+1 (Giving priority to multiply/division first?)

=9-(³∕₃÷⅓)+1

=9-³∕₉+1

=⁹∕₉-³∕₉+1

=⁶∕₉+1

=1⁶∕₉???

garypettie · March 10, 2021, 7:33pm

Hi @ToonWK, great work giving this problem a go!
Remember to do the multiplication/division first and then the addition/subtraction.
So in this case we can look at the equation as;

  9 - (3 ÷ 1/3) + 1
= 9 - (3 * 3) + 1
= 9 - 9 + 1
= 1

ToonWK · March 10, 2021, 9:41pm

I’ve finished the BODMAS lesson and I was surprise why I’ve never heard of such thing before. Whether it was on a footnote somewhere I miss or a class I miss.
I never heard of it before seriously and I will always keep it in mind going forward.