This type of sequence involves alternately adding and subtracting consecutive numbers. To find the sum of this sequence, we can group the numbers together and simplify each group as follows:

(1-2) + (3-4) + (5-6) + ... + (71-72) + 73
-1 -1 -1 ... -1 + 73

Now, we need to determine how many pairs of numbers from 1-72 there are. Since each pair yields a sum of -1, we have 36 pairs. Therefore, the sum of the sequence is:

36(-1) + 73
-36 + 73
37

Therefore, the sum of the sequence is 37.