Associative law for addition states

Associative law for addition states
  1. $(a+b)+c = a+(b+c)$
  2. $a+b = b+a$
  3. $a(b+c) = ab+ac$
  4. $a+0 = a$

Solution

Grouping does not affect the sum.

Asked in: IMO

Practice more RATIONAL NUMBERS questions on Aicharya