why number 8549176320 is one of a kind?

If I put in one canary per cage, I have one bird too many. If I put in two canaries per cage, I have one cage too many. How many cages and canaries do I have?

A doctor and a boy were fishing. The boy was the doctor’s son, but the doctor was not the boy’s father. Who was the doctor?

You need to climb ten stairs. At every stair, you can either take one step up or you can jump two steps up.

In how many different ways you can climb 10 stairs?

What runs around the whole yard without moving?

How many times can you subtract the number 5 from 25?

Can it be possible to build a house that has all its four walls facing towards the South?

There are 2 people near the river and both of them want to get on the other side. The boat can only take one of them. But they got across.
How?

A river should be crossed by a father, a mother and their two sons and two daughters.
There are some rules that should be followed while crossing the river. There can be only two people in the raft while crossing. The daughters cannot be with their father unless there is the presence of the mother. The sons cannot be with their mothers unless the father is present. Unless the guard is on the board, the criminals cannot be with any of the family members. Only the adults like the father, the guard, and the mother knows to use the raft.

How will they cross the river?

Can you solve this amazing hard number series problem?
7, 8, 10, 12, 16, 18 ?