The apartments in brian's apartment house are numbered consecutively on each floor. the sum of his number and his next-door neighbor's number is 1419. what are the two numbers?

If sum of numbers (a) +(b) is 1419 and
(a)  and (b) are neighbors , whe have:
a + b = 1419 and b-a = 1;
<=> a + b = 1419  and  a = b-1 ; 
so we have  b-1 + b = 1419 <=> 2b = 1420 <=> b=710 and a = 709
710 and 709

You should the number they give you 1419 and divide that by two since there is only to people and you get your answer 709.5

820,000 is the answr