Question

Classrooms on one side of the drama building are all numbered with consecutive odd integers. If the first room, the room with the smallest classroom number, on this
side of the building is numbered d, write an expression ind for the sum of the first five classroom numbers in a row. Then simplify this expression
The sum of the first five classroom numbers in a row is

Answer 1

Consecutive odd integers skip even numbers, so when you're describing these in general, there's a 2-number gap between them, such as 5, 7, 9, etc.

first room number:         d

second room number:   d+2

third room number:        d+2+2 = d+4

fourth room number:      d+4+2 = d+6

fifth room number:          d+8+2 = d+8

So the sum will be:

  d + d+2 + d+4 + d+6 + d+8 = 5d+20