How many pluses should we put between the digits of 987654321 to get a total of 99, and where?

Find The Next Number in the series:

12 13 15 17 111 113 117 119 123 ?

You are provided with a grid (as shown in the picture). Can you fill the squares with numbers 1-8 in a manner that none of the two consecutive numbers are placed next to each other in any direction (vertically, horizontally or diagonally?)

A worker is to perform work for you for seven straight days. In return for his work, you will pay him 1/7th of a bar of gold per day. The worker requires a daily payment of 1/7th of the bar of gold. What and where are the fewest number of cuts to the bar of gold that will allow you to pay him 1/7th each day?

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?

You see me once in June, twice in November, and not at all in May. What am I?

There is one thing that goes round the house and also inside the house but never even share a brief touch. What is it?

Can you think of a smallest +ve number such that if we shuffle the digits of the number, the new number becomes double the original number?

How many sides does a circle have?

There are are five things wrong with this sentence; only geniuses will be able to to spot all of the mitstakes