Hi, my name is Leanne and I am in grade 9. I am just learning BEDMAS and me and my mom can't agree on whether or not I am doing it right. The problem is
6 + 3 - 2 x 3 =
My mom says the answer is 3 but I say it is 12.
My mom did 2 x 3 first then came up with 6 + 3 - 6 = 3
but I said it was 6 - 3 + 6 = 9
Please let us know the answer. Thanks
Hi Leanne,
I suppose you did
6 + [(3 - 2) x 3 ] = 6 + [1 x 3] = 6 + 3 = 9,
while your mom did
[6 + 3] - (2x3) = 9 - 6 = 3.
Well on that matter, one rule says "moms are always right!" Another rule says "in an unparenthesized expression, you should do the multiplications and divisions first (from left to right), then the additions from left to right. Both these rules agree in this case: the rule says that you should parenthesize the expression as your mother did.
On this matter, the rule I prefer is "people should always formulate their questions as precisely as possible to avoid confusion". If they want you to compute [6 + 3] - (2x3), why don't they write [6 + 3] - (2x3) instead of 6 + 3 - 2 x 3?
We have had some queries about companies using such questions in contests: These questions seem to be designed so that if people answer 3, they tell them the answer is 9, and if they answer 9 they are told that the answer is 3, so nobody gets the prize. For example.
On the other hand, you can also use these unparenthesized expressions to devise puzzles such as this one:
Put in parentheses to make the equation true: 6 + 3 - 2 x 3 = 21
Claude