What has many keys but can’t open a single lock?

Spot 5 differences in two Christmas tree below:

A bag contains 64 balls of eight different colours. There are eight of each colour (including red). What is the least number you would have to pick, without looking, to be sure of selecting 3 red balls?

The product of three consecutive numbers is 7980.
Then the sum of these consecutive numbers would be?

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

Can you replace the X (both small and big x) with the numbers between 1 to 19 such that all the rows of 3 numbers between X (big x) sum to 23?

Whats the next number in the below number sequence pattern.

How can you write nineteen in a manner that if we take out one, it becomes twenty?

Find a 9-digit number, which you will gradually round off starting with units, then tenth, hundred etc., until you get to the last numeral, which you do not round off. The rounding alternates (up, down, up ...). After rounding off 8 times, the final number is 500000000. The original number is commensurable by 6 and 7, all the numbers from 1 to 9 are used, and after rounding four times the sum of the not-rounded numerals equals 24.

Can you guess the name of the month by looking the below rebus ?