Use only one mathematical symbol and all numbers (0-9) to get a sum of 99

There is a wide field of corn. A goose finds its way into the field and starts running. Can you find out till which point the goose can run into the field?

They came out at night, without being called.
They lost at day, without being stolen.
Who are they?

As you can see that fifteen matches have been used to form an arrangement. What you have to do is remove any six of them to make them ten.

We have four gears with below features=> Both Gear A and D has 60 teeth=> Gear B has 40 teeth=> Gear C has 20 teeth=> Every two minutes, Gear B makes 25 full turns.What is the relative speed of Gear A and Gear B?

Take 9 from 6, 10 from 9, 50 from 40, and leave 6.

How Come ??

There are 2 sand hourglasses.

The small one can measure 5 hours and the large one can measure 7 hours.

How can we measure 16 hours with 2 sand hourglasses running together ?

What has many teeth, but cannot bite?

What is the four-digit number in which the first digit is one-third the second, the third is the sum of the first two, and the last is three times the second?

Make eight squares by moving only two matchsticks.
Note- Square can be of different sizes.