A long ladder, its steps are divisible by 2, 1, 2 is divisible by 3, 4 is divisible by 5 and 5 is divisible by 6. How many steps are there?

In this way, the topic is compressed and simplified, which is convenient for thinking. There are five conditions in the problem, which can be solved in two steps.

The first step, according to the four conditions of "order divided by 2 is 1, order divided by 3 is 2, order divided by 5 is 4 and order divided by 6 is 5", we know that as long as 1 is added in order, it is a multiple of the four numbers 2, 3, 5 and 6.

The least common multiple of 2, 3, 5 and 6 is: 30.

So 29 (30- 1) is the smallest natural number that satisfies these four conditions.

The second step, the fifth condition is "divisible by 7", and 29 is obviously not satisfied. How can we meet this condition? Taking 29 as the base, add the least common multiple 30 of 2, 3, 5 and 6 continuously, and you can get: 29+30 = 59 59+30 = 89 89+30 =119 ... After calculation, if it can be divisible by 7, then the answer is found. Here 1 19÷7= 17 has reached the target, so it is unnecessary to add it. 1 19 is the minimum number of steps.