what is the proper way to write a substraction problem? Can it be as follows:
12
2
- 3
===
____
I was told that an addition sum would be proper to write this way, ie:
12
2
+ 3
===
____
But you cannot represent substraction in this manner as the 2 in the first example is positive. The expected answer for the first example is 7. I know that this looks really basic, but I was told by someone that this was so. Would appreciate your input into this, logic for it plus any reference.
Regards,
You seem to be asking about how to write these arithmetic questions in the column format common in elementary school.
For addition multiple rows (properly aligned) are OK because addition is associative. It does not matter how you arrange the parentheses in $$ (12 + 2) + 3 = 12 + (2 + 3) = 12 + 2 + 3 . $$ I have never seen anyone write a multirow subtraction problem, and would hate to see subtraction taught that way. I suspect that what is meant in your example is $$ 12 + 2 + (-3) . $$