What's the first and third quartile of - 5, - 4, - 3, - 2, - 1, 0, 1, 2, 3, 4, 5, 7, 7, 7

There are 14 total numbers.

Make a list of the 7 lowest numbers:

-5, - 4, - 3, - 2, - 1, 0, 1

The first quartile is the middle value of the lower half of numbers

Since there are 7 numbers (odd number), the middle value is the middle number, which is - 2

Now make a list of the 7 highest numbers:

2, 3, 4, 5, 7, 7, 7

The 3rd quartile is the middle value of the higher half of numbers.

Again because there are 7 numbers (odd number), the middle value is the middle number, which would be 5.

First quartile = - 2

Third quartile = 5