3 x 3 + 3 = 12 and not 18 because multiplication takes precedence over addition. Why is it like that?
-> Why does multiplication take precedence?
Asker: Mary, 12 years old
Answer
Dear Marie,
It’s just an agreement between mathematicians to simplify notation (more specifically, to save on parentheses).
Without that agreement, you would always have to write your example as (3 x 3) + 3 = 12 (which is still allowed, by the way, but no longer necessary after such an agreement).
Humans aren’t very good at deciphering formulas with a lot of parentheses, and that limits the number in more complicated formulas.
By the way, you could just as well agree on that priority rule the other way around, and then 3 x 3 + 3 = 18 …
Philippe J. Roussel
Imec
Answered by
Ing. Philippe Roussel
Microelectronics Reliability
IMEC
Kapeldreef 75 3001 Leuven
http://www.imec-int.com
Kapeldreef 75 3001 Leuven
http://www.imec-int.com
.