Sagot :
the sum means x+y=sum
the sum of 2 and 1 is 3
then you subtract 3 (sum) from 6 or take 3 away from 6 or 6-3=3
theh subtract 3, 3-3=0
so
-(2+1)+6-3 or 6-(2+1)-3=0
the sum of 2 and 1 is 3
then you subtract 3 (sum) from 6 or take 3 away from 6 or 6-3=3
theh subtract 3, 3-3=0
so
-(2+1)+6-3 or 6-(2+1)-3=0