Idon’t understand why it has 3 numbers when there is only supposed to be 2

Prove that the sum of two consecutive exponents of the number 5 is divisible by 30.if two consecutive exponents are 5n and 5n + 1, then their sum can be written as 30.

Consider the proof. given: segment ab is parallel to line de. prove: what is the missing statement in step 5?

Afarm that has 4 x 10^2 acres has 1.2 x 10^5 cattle. what is the average number of cattle per acre? write the answer in scientific notation. answere asap