To find the numbers that are divisible by 9, I need to look at the multiples of 9 in the given range. The smallest multiple of 9 that is greater than or equal to 150 is 153, which is 9 times 17. The largest multiple of 9 that is less than or equal to 300 is 297, which is 9 times 33. So the numbers I'm looking for are of the form 9k, where k is an integer between 17 and 33, inclusive. There are 33 - 17 + 1 = 17 such values of k, so there are 17 natural numbers between 150 and 300 that are divisible by 9. 
How many natural numbers between 150 and 300 are divisible by 9?